Solve Area and Perimeter of Similar Figures

The scale factor from figure A to figure B is 4.  How many times larger is the perimeter of B than the perimeter of A?

• 4

• 16

• 8

• 2

The scale factor from figure A to figure B is 4.  How many times larger is the area of B than the area of A?

• 4

• 16

• 8

• 2

Find y.

• 144

• 18

• 72

• 12

Suppose the dimensions of a triangle with a perimeter of 18 units are doubled. Find the perimeter of the new triangle.

• 18

• 36

• 72

• 288

Find the ratio (blue to red) of the areas.

• 4/7

• 7/4

• 49/16

• 16/49

What is the ratio of the surface areas from large to small. 

• 49/16

• 7/4

• 42/24

• 10/8

Find the ratio (red to blue) of the perimeter.

• 11/6

• 6/11

• 121/36

• 36/121

Answer explanation

REMINDER: The perimeter of similar figures is THE SAME as the ration of the side lengths of the similar figures

Find the ratio (red to blue) of the area.

• 11/6

• 6/11

• 121/36

• 36/121

Answer explanation

REMINDER: The area of similar figures is equal to the SQUARE of ratio of the corresponding side lengths

Find the ratio (blue to red) of the area.

• 4/7

• 7/4

• 49/16

• 16/49

Answer explanation

REMINDER: The area of similar figures is equal to the SQUARE of ratio of the corresponding side lengths

Find the missing perimeter.

• 15

• 20

• 25

• 30

Answer explanation

REMINDER: The perimeter of similar figures is THE SAME as the ration of the side lengths of the similar figures