1. Section 5.3A: Similar Triangles
Objectives: • Review Proportions.
• Define similarity
• Determine if two triangles are similar.
• Use similarity to solve for parts of triangles.

2. Concept: Solving Proportions Review
Ex: 2 is to 3 as x is to 48
To solve proportions we:
1. Cross multiply 3x
= 96
2. Solve for x
__ __
3x = 96
x = 32

3. Concept: You Try!!! 3 x ____ = ____ 2 18 2x = 54 2 2 x = 27
3 is to 2 as x is to 18. 3 x
____ = ____ 2 18
Now cross
multiply 2x = 54 2 2 x = 27

4. Concept: What does “Similar” mean?