Question

Circle A has radius 4 feet .Circle B has

radius 9 feet .What is the ratio of the area of arcle A to the
area of circle B?

a . 1/2
b . 4/9
c . 8/27
d . 16/81​

Answer 1

d. 16/81

Explanation:

The formula of an area of a circle:

`A=\pi r^2`

r - radius

The ratio of the areas of the difference circles:

`(A_1)/(A_2)=(\pi r_1^2)/(\pi r_2^2)=(r_1^2)/(r_2^2)=\left((r_1)/(r_2)\right)^2`

We have

Circle A: r₁ = 4ft

Circle B: r₂ = 9 ft

Substitute:

`(A_A)/(A_B)=\left((4)/(9)\right)^2=(16)/(81)`