Question

"If you double the radius of a circle, by what factor does the area increase?"

a. 8
b. 4
c. 1/2
d. 2
e. 16
Before you can do this, you need an equation relating the radius to the area (A= pi *r^2)

Answer 1

The correct answer is B.

Explanation:

Original area: A = πr²

New Area: A = π(2r)² = 4πr²

So if the radius of a circle is doubled, the area of the circle is increased by a factor of 4.

The correct answer is B.