Question

Circle A has radius 4 feet. Circle B has radius 9 feet. What is the ratio of the area of circle A to the area of circle B?

Answer 1

Answer:

$\large\boxed{\dfrac{16}{81}}$

Step-by-step explanation:

The formula of an area of a circle:

$A=\pi r^2$

r - radius

Circle A:

radius = 4 ft. Substitute:

$A_A=\pi(4^2)=16\pi\ ft^2$

Circle B:

radius = 9 ft. Substitute:

$A_B=\pi(9^2)=81\pi\ ft^2$

The ratio:

$\dfrac{A_A}{A_B}=\dfrac{16}{81}$