1. 7-5 Vocabulary
Indirect measurement
Scale drawing
scale

2. 7-5 Using Proportional Relationships
Geometry

3. Indirect Measurement
Any method that uses formulas, similar figures, &/or proportions to measure an object.

4. Ex. 1
Tyler wants to find the height of a telephone pole. He measured the pole’s shadow & his own shadow & then made a diagram. What is the height or h of the pole? h
5 ft 9 in
7 ft 8 in ft 4 in

5. Scale drawing
- represents an object as smaller than or larger than its actual size. The drawing’s scale is the ratio of any length in the drawing to the corresponding actual length.

6. Ex. 2
On a Wisconsin road map, Kristin measured a distance of 11 1/8 in. from Madison to Wausau. The scale of the map is 1 inch:13 miles. What is the actual distance from Madison & Wausau to the nearest mile?

7. Ex. 3
Lady Liberty holds a tablet in her left hand. The tablet is 7.19 m long & 4.14 m wide. If you made a scale drawing using the scale 1 cm:0.75 m, what would be the dimensions to the nearest tenth?

8. 7.5 B Similarity Ratios & Theorem
A D
B C
E F
Perimeter Ratio
Area Ratio

9. 7-5-1 7-5-1 Proportional Perimeters & Areas Thm
If the similarity ratio of two similar figures is , then the ratio of their perimeters is , & the ratio of their areas is

10. Ex 1. Given that find the perimeter P & Area A of M R 13 cm 9.1 cm Q S
P = 36 cm
A = 60 cm²
L N

11. Ex. 2 BC = 4mm, & EF = 12 mm. If P=42 mm & A = 96 mm² for
Find the perimeter & area of