Princess' scribepost for December 9, 2010

HELLO(:

So, today in class we learned a little about Similar Triangles. We learned how to determine if two triangles are similar or not. Also, we learned how to use similar triangles to determine a missing side length.

We learned a few terms:
"≅" means "is congruent to"
Congruent- same shape, same size

"~" means "similar to"
Similar- proportional in size

Corresponding Angles/Sides- have the same relative position in a figure









Then we learned that two triangles are similar if:

• two pairs of corresponding angles are congruent (therefore the third pair of corresponding angles are also congruent) WHY? Because the angles of each triangle are equal to 180°.
• the three pairs of corresponding sides are proportional.

After that, we looked at a pair of triangles and figured out if they were similar or not.
*notice that the vertices are always going to be capitalized*






To find out if they were similar or not, we found out if the side lengths were proportional.

Since they are all proportional, the pair of triangles are similar.

Then, we looked at another type or triangle called an Isosceles Triangle.

With this triangle we learned how to find missing side lengths.
For example:
a= 3
e= 6
f= 10
h= ?











We did a few more:
d= 7
h= 5
a= 4
f= ?












A to D= 6
e= 9
f= 12
c= ?
a= ?
h= ?














HOMEWORK:

• Read from this site
• Practice - odds or even
• Apply - odds or even

If I made any mistakes please feel free to comment(: