Question

Circle D was dilated to form circle D prime. The diameter of circle D is 5 units and the diameter of circle D prime is 15 units. What is the relationship between the areas of circle D and circle D prime?

Answer 1

• A' = 9A

Explanation:

Area formula:

• A = πd²/4

Area of circle D:

• A = π(5²)/4= 25/4π

Area of circle D'

• A' = π(15²)/4 = 9*25/4π = 9A

Required relationship:

• A' = 9A