You will use the ratio of two similar figures to find their

perimeter and area.

Theorem 10-7

If the similarity ratio of two similar figures is a/b, then

• the ratio of their perimeters is a/b

• the ratio of their areas is a2/b2

Perimeters and Areas of Similar Figures

Find the ratio for the perimeter for the following similar

figures.

5m13m

5/13

Now, find the ratio for the area for the following similar

figures.

5m13m

25/169

If the area of the larger figure is 439m2,

find the area of the smaller figure.

5m13m

25/169 = x/439

169x = 10975169 169

x = 65m2

AssignmentWorkbook

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