Question

the perimeter of the starfish is 30 centimeters. This original picture is to be enlarged in both dimensions to an image that is similar to the original picture. If the area of the enlarged image is 9 times the area of the original picture, what is the perimeter in centimeters of the starfish in the enlarged image?

Answer 1

area = k * length ratio^2


sqrt (9) = 3 times length ratio

3*30 = 90

in other words for similar figures, 3 times a length gives 9 times the area