Prove Triangles Similar by AA

6.4

Another Postulate

All you need are any 2 congruent angles for 2 triangles to be congruent

Why only 2 angles?

• We know that the sum of the interior angles has to be 180.

• Therefore, the third angle also has to be congruent.

Are the 2 triangles similar? Why or why not?

yes

Are the 2 triangles similar? Why or why not?

yes

Are the 2 triangles similar? Why or why not?

yes

Are the 2 triangles similar? Why or why not?

no

Are the 2 triangles similar? Why or why not?

no

Are the 2 triangles similar? Why or why not?

yes

Are the 2 triangles similar? Why or why not?

no

Are the 2 triangles similar? Why or why not?

yes

Are the 2 triangles similar? Why or why not?Can’t tell

Are the 2 triangles similar? Why or why not?

Yes

Are the 2 triangles similar? Why or why not?

Yes

Are the 2 triangles similar? Why or why not?

Can’t tell

Are the 2 triangles similar? Why or why not?

yes

Are the 2 triangles similar? Why or why not?

yes

Are the 2 triangles similar? Why or why not?

yes

Find the length of x, then find BD

Find the length of x, then find BD

Proportion Word Problems

• Molly wants to know the height of the flagpole in front of the town hall. She sees that it casts a shadow 24 ft long. She drives a stake into the ground beside the flagpole. The stake is 4 ft high with a shadow 2 feet long. How tall is the flagpole?

• The scale on a map says that 1 inch equals 150 miles. How many miles apart are two cities if you measure 4 ½ inches between them?