11.3 Perimeters and Area of Similar Figures Similar Polygons

11.3 Perimeters and Area of Similar Figures

Similar Polygons

Remembering Similar Polygons

Similar polygons have all the Angles congruent and the Sides have the same ratios. (like these three houses)

Remember this Theorem

If two polygons are similar (equal angles and corresponding sides in ratios), then the perimeters ratio is the same as the scale factor.

Perimeters are 24:16 same ratio as 3:2 for the sides

Theorem

If two polygons are similar (equal angles and corresponding sides in ratios), then the Area ratio is the same as the scale factor squared. (in the regular hexagons)

6

2

1:91:3

1:32:6

22

RatioArea

RatioPerimeter

Find the Area and Perimeter

The given figures are similar

8 5

60

32

Area

Perimeter

Area

Perimeter

How would you find the area?

Find the Area and Perimeter

The given figures are similar

8 5

60

32

Area

Perimeter

Area

Perimeter

?:6025:645:8

?:325:8

22

RatioArea

RatioPerimeter

Find the Area and Perimeter

The given figures are similar

8 5

60

32

Area

Perimeter

Area

Perimeter 20

208

160

325832

5

8

P

PP

Find the Area and Perimeter

The given figures are similar

8 5

60

32

Area

Perimeter

4375.23

20

Area

Perimeter

4375.2364

1500

60256460

25

64

A

AA

Homework Page 679-680# 8 – 24,

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