Question

A circular picture is 8 inches in diameter.

Part A


What is the area of the picture in square inches?


A. 4π square inches

B. 8π square inches

C. 16π square inches

D. 32π square inches


Part B

A frame that is 2 inches wide surrounds the picture. What is the total area of the picture and the frame in square inches?


A. 4π square inches

B. 12π square inches

C. 36π square inches

D. 40π square inches

Answer 1

Part A C. 16π square inches

Part B C. 36π square inches

Explanation:

If we know the diameter, we can calculate the radius

d= 2r

8 = 2r

Divide by 2

8/2 =2r/2

4=r

The radius is 4 inches

Area of a circle is

A = pi *r^2

A = pi *4^2

A = 16 pi inches^2

Part B

If the frame is 2 inches wide, we add 2 to the radius

r = 4+2=6

A = pi r^2

A = pi *6^2

A = 36pi inches ^2