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AP® Calculus AB-BC

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Moderate

Rate of Change: Area of a Circle

APCALC-KDEHN8

The circumference of a circle, $C$, is increasing at a rate of $2 \, \text{cm/s}$. Find how fast the area is increasing when $r=6\,\text{cm}$?

A

$\cfrac{1}{\pi} \ \text{cm}^2 /\text{s}$

B

$2\ \text{cm}^2 /\text{s}$

C

$12\ \text{cm}^2 /\text{s}$

D

$12\pi \ \text{cm}^2 /\text{s}$