What is the percentage increase in area when ordering a 14 inch rather than a 12 inch pizza?
A) 16%
B) 26%
C) 36%
D) 46%

Question

Quizplus · Accepted Answer

The area of a circle is given by the formula $A = \pi r^2$, where $r$ is the radius. For a 12-inch pizza, the radius is 6 inches, and for a 14-inch pizza, the radius is 7 inches. The area of the 12-inch pizza is $\pi(6)^2 = 36\pi$, and the area of the 14-inch pizza is $\pi(7)^2 = 49\pi$. The increase in area is $49\pi - 36\pi = 13\pi$, which is a $13\pi / 36\pi = 13/36$ increase. Converting this fraction to a percentage, $13/36 \approx 0.3611$, or approximately 36%.

What Is the Percentage Increase in Area When Ordering a 14