## Wednesday, October 27, 2010

### Josh's Blog Post

Mr.Backe the email you sent me for the invitation expired so I couldn't really do anything. Sorry for not clicking it a while back so I asked Alvin too let me use his blogger account to do my post.
So in class today we learned the following:add proper and improper fractions; when adding fractions, the denominators must agree, that is, they must be the same. When fractions do not have a common denominator, find a common denominator for both fractions before adding. Add only numerators and keep denominators the same.

1/4 + 1 / 4 = 1 + 1/4
= 2/4
= 1/2

When your subtracting fractions, your doing the same thing like adding. When subtracting fractions, denominators must stay the same. When fractions do not have a common denominator, find one for both fractions before adding. Add only numerators and keep denominators the same.

1/2 - 1 /6 = 3/6 - 1/6
= 2/6
= 1/3

2 1/4 + 3 1/4 = 2 + 3 + 1/4 + 1/4
= 5 2 / 4
= 5 1/2

SUBTRACTING MIXED NUMBERS :
when subtracting the whole numbers first deal with the fractions as you did in the previous example unless you need to re group.

6 1/5 - 3 5/10 = ( 6 - 3 ) + ( 1 /5 - 5 / 10 )
= 3 + ( 2/10 - 5/10 )
= 2 + ( 10/10 + 2/10 - 5 / 10 )
= 2 + 7/10
= 2 7/10

I'm done my blog thats all I can recall from today. Sorry, I couldn't use paint too make it more clearer wouldn't let me add image so I did it like that. Brendans got your next blog

### Alex's Post

Hurrah it's my post thanks Jo for switching it at the last minute.Its a day late but I'm still going to use the word today.
Okay today in class we made 2 foldables, yes 2, one was for the Real numbers, Natural, Whole, Integers, Rational, and Irrational numbers. I made the pictures in paint because it's too hard to take the pictures. The first image is the front and second page and the second is the inside of the 1st foldable. We basically just put what is in the set, what numbers go in each category, the numbers that don't belong in each set, and numbers we don't usually think of. For homework with this we were supposed to finish all the things we didn't do and add the definitions.

This lovely little picture here is the second foldable, well half of it at least. Mr. Backe explained how to multiply improper fractions, proper, and mixed numbers, and how to divided them as well.
The homework for this was to make 10 questions each for dividing and multiplying using the way he showed us.

Yeah yeah I know its not great but I'm me what did you expect. If you didn't understand something or I missed something leave a comment.
Oh yeah and as I said already today Josh, your doing the next one.
(reminder click on the images to enlarge.)

## Friday, October 22, 2010

### Jomari's Scribepost October 22, 2010

Dividing Decimals
To start out class, we multiplied a few numbers. One of the interesting questions was 0.1x100.

0.1x100 = 10 because 1x100=100 Once you find 100 you just put the decimal place in. This will help us when we do our division.
One more question is 0.1 x 1
0.1x1 = 0.1 Because anything multiplied by ONE will equal ITSELF

After doing these questions, we were told that anything divided by 0 is not zero but undefined.
We then went on to learn about dividing.

Here is the first question:

We were not allowed to use calculators so we did this the long way.
We first thought about what you do when you divide.
Dividend ÷ Divisor = Quotient To make this question easier, we need to change the divisor (2.5) into a whole number.
To change the divisor into a whole number, we need to multiply it by 10.
If we multiply the divisor by 10 then we need to multiply the dividend by 10.

2.5x10=25
1.265x10=12.65

Now we solve the question
To start, we have to find out how much times 25 fits into 12. It fits into twelve 0 times. so we put a zero on top. We also need to line up the decimals so we know that the answer is less than 1.

We then find out how much times 25 fits into 126 because it does not fit in 12.
It fits 5 times so we put that on top.
We multiply 25 by 5 to get 125 and we then subtract that. But we still need to line up the decimals.

How much times does 25 fit into 15? 0. Because of this we need to add a zero after the 5 at the answer and after the15. How many times does 25 fit into 150?6. So we add a 6 to our answer. We then multiply and subtract.
25x6=150

Because we end up with 0, we now have the answer, 0.506
We thought that we have to convert the answer because we changed the dividend and the divisor but we don't have to change the answer because
the changed numbers were equivalent to the original so dividing them would give you the same equivalent answer.
For Homework we had to do all the division questions in the yellow book.
Thanks for reading( if you actually did)! Please correct me and make suggestions on how to improve my post
For the next post I pick Josh? Alex. Fo' Sho

## Wednesday, October 20, 2010

### Jeric's Scribe Post for October 20, 2010

Hi guys, today in class we did some questions. The question was what numbers fit in between 1/8 and 1/10.

Well first of all most people in our class said that 1÷10=0.1 which is true but then we were asked to do it another way. Jamie said that 1/2 of 1/4 = 1/2 x 1/4 = 1/8. Then I think Guiseppe said 1/4 / 2. What Guiseppe did was a complex fraction.

Then we were told that we could do it this way ...

We were first asked if 8 could go into 1 and common sense no. Then we were told that by adding a decimal point after 1 still means 1. But instead of looking at it as 1.0 just look at it as 10. But by adding the decimal we must also place the decimal in our answer and during our process of finding out what we did. So then we were then asked how many times does 8 fit into 10 and its 1. We then subtracted 1.0 to 0.8 to get 0.2. Since 8 can't go into 0.2 you can place another 0 after 0.2 to make it 0.20. It is still 0.2 but by placing the 0 it makes it look like its 0.20. So then we were asked how many times does 8 go into 0.20 and it equals 0.16. You then subtract 0.16 from 0.20 and get 0.04. Once again 8 does not fit into 4 but by placing a 0 in front of the 4 it looks like 0.040. We were then asked how many times does 8 go into 40 and it equals 5 times. We then subtract 0.040 by 0.040 which is 0. You then should have an answer of 0.125.

We then had to convert 1/10 into a decimal which was pretty easy.

Once again by placing the decimal it would look like 10. So then we were then asked how many times does 10 go into 10. We got 1 and then you subtract 1.0 from 1.0 to equal 0. You should then have an answer of 0.1.

Now that we have converted the fractions into decimals we then asked what numbers fit between 0.1 and 0.125.

We came up with answers like 0.101, 0.102, 0.103,0.104

These answers are correct. How do we know ? As long as the first 3 digits are the same then anything after the that is between 0.1 and 0.125.

Sorry if none of this makes sense.

Thnx :D
I CHOOSE JOMARI FOR THE NEXT BLOG !!!

## Tuesday, October 19, 2010

### Sharmaine's Scribe Post

Today in math class, we had a quiz on Rational Numbers
We had five questions and they were:

1. Name a rational number equivalent to 5/25
A rational number that is equivalent to 5/25 can be
10/50, 0.2 , 1/5 and more because they all represent the same amount.

2. 6.7, 0.8, 0.666...., 3/4
Write in ascending order
Ascending means least to greatest, so the order would be
0.666... , 0.8, 6/7, 13/14

How i got this was i converted the fractions into decimals
6/7 =0.86
13/14 =0.92

3. Name a rational number that is not an integer.
that means that its can be expressed in a rational number but not a integer
so like 1.5, 1/5, 2/10, 3/10

4. Name the points at the balck and blue dots in the number line.
red = -5.5 blue = 3.2

5. The number 6 belongs to what group
N,W,I,Q, and R
natural numbers
whole numbers
integers

rationals (fractions)
real number

Once we were done that we wrote down notes on how convert a repeating decimal back into a fraction.

we started off by knowing how many periods a decimal would have.
for example - 0.14 reapeating, there are 2 period because there are two number that kept reapeating which would be 0.14141414..

if it was one number repeating there would just be one period.

Next we found out how to convert a repeating decimals into a fraction.
ex. 0.14... (repeating)
We mulitplied it by 100 to move 2 decimals places. It was now 14.14 repeating.
Next we subtract 100x by x too get 99. "x" is like an imaginary one

"x" is 0.14
Since there were two 14 together they canceled out leaving us with 14.
we are left with 99 = 14, so we divide it over 99 because there are 99 x's .
there were two 99 so they cancel out and your left with the fractional form 14/99

You would do the same if it was only one number repeating but instead you woild mulitply it but 10 to make in move two decimal places.

Homework:
- journal
- textbook questions (we'll have a work period tomorrow)

I chose jeric to do the next scribe!!

## Monday, October 18, 2010

### Connor's Blogpost for October 18

In Mr. Backe's math class today we started off with playing a new decimal version of our previous card game.

The operation used was addition. The game basically worked by all red cards were negative decimals, black cards were positive numbers and the face cards were 0.9 and its opposite. The cards were very simple because they were only decimals in the tenths place value and between
-1, 0, 1.

Then we continued on with making a new foldable.
We started 1/3 down the horizantal page with this image below.

If you cannot read this diagram, this is a list of what it says;
-Natural Numbers and Counting Numbers
Eg. 1,2,3,4,5,6,7,8,9
-Whole Numbers
Eg. All Natural numbers and 0
-Integers
Eg. All Numbers and the opposites
-Rational Number
Eg. All numbers that can be expressed in a/b, where a and b are integers but b cannot = 0
-Irrational Numbers
Eg. None terminating numbers, none repeating numbers, decimal numbers like Pi and square roots of none perfect squares.
-Real Numbers
Eg. All numbers in the chart excluding imaginary numbers.

The initials for the categories are;
Natural Numbers = N
Whole Numbers = W
Integers = I
Rational Numbers = Q
Irrational Numbers = Q' <--- The tick on the top right corner of the Q means prime.
Real Numbers = R

The Boxes represent that every smaller box inside the bigger box, fits under the bigger boxes category. For example Natural Numbers and Whole numbers fit under the Integers box. And all the boxes including Irractional numbers fit under the real numbers category.

This is as far as we have gotten on the foldable in todays math class.
Homework for tonight is;
Play tutpup
Decimal Booklet
2.1 Extra Practice
Text Book 2.1 Practice, Apply and Extend
Also if you havn't finished the above image on your foldable, complete that too.

THANK YOU for reading my post, Rate and Subscribe :) (Comment)

THE NEXT PERSON I PICK FOR THE BLOG IS SHARMAINE! (:

## Saturday, October 16, 2010

### Jamie's Blog Post for October 15, 2010

In math class, we were given new math sheets.

2 of the sheets Mr. Backe gave us had number lines on them. One had a horizontal number line, and the other had a vertical number line. On the first number lines on both sheets, we were asked to find 0, and label the ticks by 2.

On the other number lines, we were asked to label the ticks by 0.5. Then, Mr. Backe asked us to label where the opposite of -1.25 and 4.75 was. If you didn't know where to label them, this is where I put mine.

For homework, Mr Backe gave us MORE work sheets. We have to finish the addition and subtraction parts of the little booklet.

1 a. 89.9 + 43.3 = 133.2
2 a. 59.9 +82.82 =142.72
3 a. 91.355 + 1.88 = 93.235
4 a. 0.164 + 36.33 = 36.494
5 a. 42.53 + 69.7 = 112.23
6 a. 55.723 + 21.9 = 77.623
7 a. 93.547 + 66.81 = 160.357
8 a. 66.65 + 32.4 = 99.05
9 a. 28.6 + 7.651 = 36.251
10 a. 43.783 + 1.56 = 45.343

1 b. 11.557 + 17.001 = 28.558
2 b. 16.05 + 2.2 = 18.25
3 b. 92.3 + 86.8 = 179.1
4 b. 33.304 + 92 = 125.304
5 b. 43.068 + 65 = 108.068
6 b. 18.6 + 93.79 = 112.39
7 b. 66.87 + 91.88 = 158.75
8 b. 36.886 + 93.89 = 130.776
9 b. 18.73 + 36.1 = 54.83
10 b. 80.687 + 36.843 = 117.530

1 c. 28.43 + 32 = 60.43
2 c. 55.891 + 32.6 = 88.491
3 c. 84.54 + 61.873 = 146.413
4 c. 55.2 + 97.17 = 153.37
5 c. 97.93 + 4.8 = 102.73
6 c. 83.9 + 91.51 = 175.41
7 c. 64.823 + 85.2 = 150.023
8 c. 34.2 + 14.412 = 48.612
9 c. 64.1 + 62.2 = 126.3
10 c. 2.884 + 40.037 = 42.921

1 a. 46.65 - 16.2 = 30.45
2 a. 40.19 - 30.684 = 9.506
3 a. 51.19 - 30.3 = 20.89
4 a. 95.87 - 80.073 = 15.797
5 a. 91.6 - 18.7 = 72.9
6 a. 65.688 - 27.508
7 a. 62.274 - 46.9 = 15.374
8 a. 44.2 - 24.8 = 19.4
9 a. 100.576 - 24.7 = 75.876
10 a. 80.419 - 0.12 = 80.299

1 b. 96.85 - 12.9 = 83.95
2 b. 80.03 - 15.884 = 64.146
3 b. 94.7 - 71.11 = 23.59
4 b. 27.103 - 1.788 = 25.315
5 b. 73.08 - 37.98 = 35.1
6 b. 84.393 - 65.1 = 19.293
7 b. 95.112 - 31.2 = 63.912
8 b. 57.33 - 6.011 = 51.319
9 b. 20.5 - 11.638 = 8.862
10 b. 63.065 - 12.5 = 50.565

1 c. 80.75 - 73.65 = 7.1
2 c. 67.7 - 8.52 = 59.18
3 c. 34.3 - 4.2 = 30.1
4 c. 74.3 - 37.246 = 37.054
5 c. 50.7 - 47.518 = 3.182
6 c. 68.305 - 34.13 = 34.175
7 c. 94.5 - 26.916 = 67.584
8 c. 87 - 74.1 = 12.9
9 c. 67.19 - 20.4 = 46.79
10 c. 43.9 - 5.7 = 38.2

After Mr. Backe assigned this for homework, he let us play tutpup for 3 minutes.
REMEMBER, you should be playing tutpup everyday! :)

THEN, Mr Backe told us to go on a different math website. Feel free to go on it anytime!
BUT! There are specific things you have to check off. It should look like this:
Another thing for homework, is the textbook work!

SHOW YOU KNOW:
pg. 48
Compare the following rational numbers. Write them in ascending order and decending order.
-1, -3/4, -0.6, 0.3, 1 1/5

pg. 49
3/5

pg. 50
-49/20 = -2.45

1. I would tell Laura to place 2 1/2 on a number line. Then, I would tell her to place the OPPOSITE of 2 1/2 on the number line. Therefore, Laura would place -2 1/2 correctly on the number line, since 2 1/2 is the exact distance away from zero as -2 1/2, except it's on the left side of zero.

2. Dominic is not correct. 3.1 is greater then 2.5, but -3.1 is NOT greater than -2.5.
As shown on the number line, -2.5 is greater than -3.1. Once the numbers become negatives, the numbers closer to zero are always greater.

3 a. I prefer to convert fractions into decimals. For me, it is easier to get decimals from fractions, then fractions from decimals.
b. -0.9 -7/8 = -0.88 <- -0.88 is greater than -0.9, because it is closer to zero.

THANK YOU FOR READING MY POST. SORRY IF THERE ARE NO COLOURS, BECAUSE WHENEVER I ADDED COLOURS THEN PUBLISHED IT, IT WOULDN'T SHOW.

THANK YOU.

I choose CONNOR for the next scribe thing.... :D

## Monday, October 11, 2010

### Michelle's Scribepost for October 8, 2010

Today in math class we learned the difference between visible surface area and total surface area.

Visible surface area is the part of the figure you can see without imagining the back of the imagine.

Total surface area is the whole surface area (all faces) of the figure viewed in 3D.
(Well, thats how I defined it.)

Pink (roof) : S.A.= l x w
= 4 x 7
= 28m²

Yellow (side of house) : S.A.= l x w
= 7 x 2.5
= 17.5m²

Blue (front of house) : S.A.= l x w
= 4.8 x 2.5
= 12m²

Orange (gable) : S.A. = b x h / 2
= 4.8 x 3.2 / 2
= 15.36 / 2
= 7.68m²

Then you add all the surface areas together.
28 + 17.5 + 12 + 7.68 = 65.18m²

After we did that, Mr.Backe gave us a question to solve.
(Here are some things we wrote down before, to help us solve the question)

Word: millimetre centimetre decimetre metre litre gram dekametre hectometre kilometre (American spelling is with the endings "er")
Symbols: mm cm dm (m) (l) (g) dam hm km
Prefix: mi ci di (m) (l) (g) deca(decka) heca kilo
Decimals: 1/1000(0.001), 1/100( 0.01), 1/10(0.1), 1, 10, 100, 1000

If the can is 5dm in height what is its total surface area?
1 cm is 10mm
1 dm is 10cm

First I converted all the units into cm:
36mm/10 = 3.6cm
I used cm since most of the units were cm, so it made sense to pick unit that was mostly used.

Then I found the surface area of the outside of the paint can.
= 3.6 /2
= 1.8

S.A = 2 Ï€ r ² + 2 Ï€ r h
= 2 Ï€ ( 1.8 ) ² + 2 Ï€ ( 1.8 ) ( 50 )
= 2 Ï€ ( 3.24 ) + 2 Ï€ ( 90 )
= 6.48 Ï€ + 180 Ï€
= 20.36 + 565.49
= 585.85cm²

Next I found the surface area for the inside of the paint can.
S.A.= 2 Ï€ r h
= 2 Ï€ ( 1 ) ( 50 )
= 2 Ï€ ( 50 )
= 100 Ï€
= 314.16cm²

I didn't find the circumference on the inside of the paint can because the circle part on the inside is gone since there is no lid, and also for the outside of the paint can you still have to take away the circumference of the smaller circle. All together that is two circles that are the same size, so the " 2 Ï€ r ² " cancels out.

Sorry if that didn't make sense, but I tried to explain it as best as I could.

Then you add the outside and the inside of the paint can together.
585.85 + 314.16 = 900.01cm²

** SORRY THE COLOURS DIDN'T WORK FOR ME. It kept turning into black whenever I published it.

Thank you for reading my blog, and don't forget to comment. Also correct the mistakes that I may have made, please! The next person I pick to do the blog is JAMIE!

## Sunday, October 10, 2010

### Jemineth's Blogpost

Hi guys! My apologies because this blog was supposed to be up here ages ago. Anyways, i was assigned to work on the question No.15(b) from the textbook so here it is. P.S There WILL BE MISTAKES so feel free to comment and make corrections.

No.15 (b)

Length = 12 cm
Width = 3 cm
Height = 8 cm (For those who are having troubles seeing the measurements)

#1 : Find the area of each face(Because i know that the front/ back, sides, and top/bottom are asymmetrical, what I'm going to do is solve for one face and multiply it by two, to find the other.

Top and bottom :
3 x 12 x 2 = 72 cm2
Sides :
8 x 3 x 2 = 48 cm2
Front and back :
8 x 12 x 2 = 192 cm2

#2 : Once the area of all faces has been solved, you add them all together to find the surface area of the whole figure (without the hole in the middle)

72cm2 +48cm2 +192cm2 =312cm2

#3 : Find the area of the hole in the middle of the figure. To do that use the formula of a cylinder.

2 x Ï€ x r2 + 2 x Ï€ x r x h =
First solve the first part of the formula -
2 x Ï€ x 22 = 25.12
Next solve the second part of the formula -
2 x Ï€ x 2 x 3 = 37.68
Then add those two, to solve for the final answer of the formula
37.68 + 25.12 =62.80

#4 : Add the area of the hole to the area of all the faces to find the total surface area of the whole figure including hole in the middle.

62.80+312 = 374.8cm2

#5 : Last but not the least subtract the two ends of the hole from the surface area to get the final answer.

374.8- 25.12= 349.68cm2

There is my scribe post for number 15. Remember that there were mistakes from the way i solved for the answer, so please make corrections so that when other people reads this they will get the right answer, it also helps me too! Anyways, i hope my scribe wasn't hard to understand. And DO YOUR HOMEWORK GUYS !

## Thursday, October 7, 2010

### Argie's blog post.

Okay, well today in class we were all assigned questions to make a blog about. My question was question number 19 from chapter 1.3 in our math textbooks.

The question was:
A party planner buys two plain cakes for a meal she is planning. One cake is square and the other is round. Both cakes are 6 cm think. The square cake measures 25 cm along each edge. The round cake has a diameter of 25 cm.
A) Sketch and label a diagram of each cake
B) Show how to make four cuts to create eight equal pieces for each cake.
C) Estimate and then calculate how much the surface area increases after each cake is cut and the pieces are slightly separated.

A)

B)

C) First you have to find the surface area of the whole rectangular prism.
SA = 2(lxw)+2(lxh)+2(wxh)
= 2(25x25)+2(25x6)+2(25x6)
= 2(625)+2(150)+2(150)
= 1250+300+300
= 1850 squared cm

Now you have to cut the rectangular prism into 8 equal pieces. So you divide the 25 by 8 because you are cutting it into 8 pieces.
25/8=3.125

Now find the surface area of one of those pieces.
SA = 2(lxw)+2(lxh)+2(wxh)
= 2(25x3.125)+2(25x6)+2(3.125x6)
= 2(78.125)+2(150)+2(18.75)
= 156.25+300+37.5
= 493.75 squared cm

After that has been done you have to multiply that answer by 8 because there are 8 pieces.
493.75x8=3950 squared cm

The surface area of the rectangular prism with the 8 equal pieces cut would be 3950 squared cm.

Since we just finished the rectangular prism, now the cylinder.

To find the surface area of this particular cylinder you do this...
First you need to get the radius from the diameter
r = d/2
r = 25/2
r = 12.5 cm

Now to find the surface area
SA = 2 x pi x r2 + 2 x pi x r x h
= 2 x 3.14 x 12.5 2 + 2 x 3.14 x 12.5 x 6
= 98.125 + 471
= 569.125 squared cm

Now that you have the surface area you now have to cut it into 8 pieces. So you divide the diameter by 8 to get 3.125

Now to get the surface area of the 8 slices

SA = 2 x pi x r2 + 2 x pi x r x h
= 2 x 3.14 x 3.125 2+ 2 x 3.14 x 3.125 x 6
= 61.33 +

### my blog post

okay class, we were all assigned questions, and i got question 7 from section 1.3 in our textbooks.

For the first part of question 7 it asks for the dimensions of the cut out piece. If you look at the image above the cut out piece is in the corner.

So to find the dimensions you could see that they are:
9cm, 15cm, and 17cm.

Then for part two, it asks how the cut out piece will affect the surface area for the original rectangular solid. But truth is it doesn't.

It shows the top, side, and front view of the solid, but it shows a whole surface! So the surface area stays the same because cutting out a CORNER piece will only affect the volume. But if you look at the piece at front, side, and top view. The shape looks perfectly normal!

What we learned:
The dimensions of the cut out piece is 9cm, 15cm, and 17cm

Sometimes cutting out a corner on a prism will not affect the surface area

### Noelle Cuvos' Blog Post

We were all assigned questions from the textbook or worksheet that we had to explain how we did. Honestly I got a hard question that was really hard for me at first, so you may get confused with my further explanations, so in advance I apologize.

I was assigned question 16b. The question asks:
Sorry for the uneven drawing.. -___-"

Hey Noelle, what formula are you going to use ?!

Great question. Since we're looking at a rectangle, I think we need to use a formula like this one: LENGTH X WIDTH = SURFACE AREA -- or -- l x w = A

Alright, so i started by looking on the first side length, which is the top of the image. I simply found that the whole side is equaled to the bottom 2 side lengths put together to get the whole side length in total.

When you add the 2 lengths it'll look something like this:

3.8 m + 5.1 m = 8.9 m

So looking back at the formula, we have just found the width. So far we have:

8.9m x L = A

Now I think we should look for the length.
DISCLAIMER: This is the part where it starts getting a bit more tricky and confusing.

What I did to find the length was by using the pythagorean relation. The height measurement was 7.2 but the angle of the triangle on the side ends and doesn't go all the way. So what do we do ? Subtract that side length from 7.2 like so :

7.2 - 2.9 = 4.3

So with the pythagorean relation we must have another side of the triangle to find the hypotenuse.

Alright now this is easy, the bottom shows that obviously the second leg of the triangle is 3.9m.

DISCLAIMER#2: Okay , this is the part where it will be really hard to explain and even HARDER to understand. This almost made me cry, so here we go.

The pythagorean relation:
A^2 + B^2 = C^2 (Squared)

So substitute in our numbers that we found...

8.9^2 + 4.3^2 = C^2

Now according to BEDMAS, i first have to do the exponents. So now our equation looks like this:

18.49 + 15.21 = C^2

Alright, understanding this? Okay good. Now we continue with BEDMAS... Adding:

33.7 = C^2

Now we must find the square root to find the variable of C.
______
-\/33.7 = C

5.8m=C

L = C

5.8 = L

Are we done? NO ! We have the find the surface area silly ... So we now have the proper conditions to perform the calculations on this rectangle.

Once again, the formula is:
L x W = AREA

Lets substitute our numbers

5.8 x 8.9 = Area

51.63 m^2 = AREA

Alright, well that was my post and my equation. I hope you could understand my poor description of work. I tried my best, and really worked hard. Please comment with tips to make my next blog a bit better.

Also special thanks to ALVIN ;)

### Elaine's Scribepost for October 5, 2010

Hi you guys! We each were assigned a question to do for the blog and the question I got was the one with the picture of the house.

The question was :

The surface area of walls, roofs, doors, and windows all affect the amount of heat loss from a house. Calculate the surface area for the doors,windows, walls, and roof for the house below. Express each answer to the nearest tenth of a square metre.

wi
ndo
ws = 80cm x 60cm each
doors = 205cm x 82
cm each
-back of the house is identical to the front
-sides of the house are identical to each other

I started off with the windows. Since there are 3 window in the front and 2 window on the side, and the opposite sides are equal there would be 10 windows all together [(3+2)(2)]

Here is how I got the area of the windows:

First, I converted the centimetres into metres by dividing it by 100
80/100= 0.8m
60/100= 0.6m

SA = 10(lw)
= 10(0.8 x 0.6)
= 10 (0.48)
= 4.8 squared m

Now, I will calculate the area of the doors. Since, the back and front of the house are both identical, there would be 2 doors :

I also had to convert the cm in m:

SA = 2 (lw)
= 2 (2.05 x 0.82)
= 2 ( 1.68)
= 3.36 squared m

For me, finding the area of the walls got a little tricky. What I did was find the sides of the walls, then subtracted the area of the doors and windows:

SA = 2 (lw) = 2 (lw)
= 2 ( 4.8 x 2.5) + (2.5 x 7)
= 2 (12) + 2 (17.5)
= 24 + 35
= 59 squared m

- after adding everything, together, I had to subtract the area taken up by the windows and doors.
-the area of the doors was 3.36 squared m
- but for the windows, only 8 are on the walls so I had to find the surface area of 8 windows:
SA = 8 (0.8 x 0.6)
= 8 (0.48)
= 3.84 squared m

SA = 59 - 3.36 - 3.84
= 51.8 squared m

Lastly, I have to find the area of the roof I did that using two different steps, the rectangles, then the triangles:

SA = 2(lw)
= 2 (7 x 4)
= 2 (28)
= 56 squared m

now I find the area of the triangles:
-SA =2 (b x h/ 2)
- but since the formula is multiplied and divided by two, they both cancel out
-SA = b x h

SA = b x h
= 4.8 x 3.2
= 15.36 squared m

SA = 56 + 15.36
= 71.36 squared m

-but after adding the two, I have to subtract the area of the two windows
-SA= 2 (0.8 x 0.6)
= 2 (0.48)
= 0.96

SA = 71.36 - 0.96
= 70.04 squared m

After all the work that's done, the answers are:

Windows = 4.8 squared metres
Doors = 3.36 squared metres
Walls = 51.8 squared metres
Roof = 70.04 squared metres

That is how I got all my answers. Sorry if it's kind of confusing and THANKS FOR READING MY SCRIBE

## Tuesday, October 5, 2010

### Princess' scribepost for October 5, 2010

HI STUDENTS!
Today I will be answering question 5b. This question determines the surface area of a cube with a square hole, extending all the way through the inside, in the middle of the figure.

5b)

S.A = 2[6(6)] - 2[2(2)] + 4[6(6)] + 4[6(2)]
= 2(36) - 2(4) + 4(36) + 4(12)
= 72 - 8 + 144 + 48
= 256cm²

Okay, I'm not sure if this was understandable or not, because I know I didn't really explain anything, and I apologize!! It's because I don't know how to explain things, I hope the pictures and formula was enough though.
Thank you for reading my blog post (:

[ P.S. I tried very hard to fix this, BUT I don't know why the colors aren't showing ): ]