Similar Triangles

7-3 Triangle Similarity:

AA, SSS, and SAS

Engineers use similar triangles when designing buildings, such as the Pyramid Building in San Diego, California.

Who uses this?

E X A M P L E 1

Using the AA Similarity
Postulate

Explain why the triangles are similar and write a similarity statement.

Verifying Triangle Similarity

E X A M P L E 2

Verify that the triangles are similar.

Verifying Triangle Similarity

E X A M P L E 2

Verify that the triangles are similar.

Multiple Choice

How do these triangles appear to be similar?
(Hint: Look for non-labeled parts!)

• AA
• SAS
• SSS
• Not Similar

Multiple Choice

Are these triangles similar? If so, why?

• AA

• SAS

• SSS

• Not Similar

Multiple Choice

Are the triangles similar, if so state how.

• AA

• SAS

• SSS

• Not similar

Explain why △ABC ∼ △DBE and then find BE

E X A M P L E 3 Finding Lengths in Similar Triangles

Multiple Choice

These triangles are similar. Find missing side...

• 5

• 7

• 9

• 11

Multiple Choice

The pair of figures are similar. Find the missing side.

• x = 12

• x = 3

• x = 40

• x = 4

E X A M P L E 5 Engineering Application