1. Review Quiz:
1. Maria is 4 ft 2 in. tall. To find the height of a flagpole, she measured her shadow and the pole’s shadow. What is the height h of the flagpole?
2. A blueprint for Latisha’s bedroom uses a scale of 1 in.:4 ft. Her bedroom on the blueprint is 3 in. long. How long is the actual room?
25 ft
12 ft

2. Parts of Similar Triangles
Section 6-5

3. Proportional Perimeters Theorem
If 2 triangles are similar, then the perimeters are proportional to the measures of the corresponding sides.

4. Example: Using Ratios to Find Perimeters
Given that ∆LMN~∆QRS, find the perimeter P of ∆QRS.
The similarity ratio of ∆LMN to ∆QRS is
So the ratio of the perimeters is also 13/9.1.
The perimeter of ∆QRS is 25.2 cm.
13P = 36(9.1)
P = 25.2

5. The perimeter of ∆ABC is 14 mm.
Example:
∆ABC ~ ∆DEF, BC = 4 mm, and EF = 12 mm. If P = 42 mm for ∆DEF, find the perimeter of ∆ABC.
12P = 42(4)
P = 14 mm
The perimeter of ∆ABC is 14 mm.

7. Example: Using the Triangle Angle Bisector Theorem
Find PS and SR.
x = 30

8. Example:
Find AC and DC.
y = 18
So DC = 9 and AC = 16.

9. Lesson Quiz: Part I
Find the length of each segment.
SR = 25, ST = 15

10. Lesson Quiz: Part II
3. ∆ABC ~ ∆DEF. Find the perimeter of ∆ABC.
P = 27 in.