## Tuesday, October 5, 2010

### DARNELL'S QUESTION ?!

HEY CLASS,
So today i was picked for a math question. The question i got WAS:
Jixuan has 64 centimeter cubes. He used all of them to build a rectangular prism. What is the maximum surface area that he could construct?

SO! I took some time on this question. It was a pretty hard question, but once i got some help from my wonderful fellow peers, I finally knew how to do it!

Lets get started.
Jixuan has 64 centimeter cubes.
He used all of them to build a rectangular prism.
Whats the maximum surface area?

So I had to construct a rectangular prism with 64 centimeter cubes. It's pretty hard to build a rectangular prism with this much cubes. There are 6 sides to a rectangular prism. All the sides could be even just like a cube, or not even like a 3D rectangle. If you divide 64 by 6 your answer will be like:10.66666666666667

So now i know that the prism will be constructed like a rectangle, and the sides will not be even. What i did was try to create with 64 centimeter cubes. DON'T TRY TO MAKE THE MAKE THE CUBE EQUAL 64, OR USE 64 CUBES ON EACH SIDE BECAUSE THOSE WE'RE MY MISTAKES! You need to use 64 cubes to make a rectangular prism!

Here is the rectangular prism i created using 64 cubes:
Width = 2 cm
Length = 8 cm
Height = 4 cm
An easy way to know you have used 64 cubes is by multiplying the Depth x Width x Height and it should equal how many cubes you have in the rectangular prism.
Now for the Surface Area part of the question!
SA = (Surface Area)
SA =2 (length x width) + 2 (length x height) +2 (height x width)
= 2 (8 x 2) + 2 (8 x 4) + 2 (4 x 2)
= 2 (4) + 2 (32) + 2 (8)
= 8 + 64 + 16
= 88 cm2

IF I'M WRONG, PLEASE COMMENT AND EXPLAIN HOW TO GET THE ANSWER :)

#### 1 comment:

1. Whoa! Good job Darnell! I like the way you told us about your mistakes. You explained it well. I also like your use of colours, it makes your blog look interesting and not boring. :D