# Chapter 8 - Section 8.4 - Circumference and Area of a Circle - Exercises - Page 372: 3

C = 66 in A = 346$\frac{1}{2} in^{2}$

#### Work Step by Step

Given the radius of the circle = 10$\frac{1}{2}$in = $\frac{21}{2}$ in The circumference of the circle is given by the formula c= $\pi$ d = 2$\pi$ r =2 * $\frac{22}{7}$ * $\frac{21}{2}$ = 66 in The area A of a circle whose radius has length r is given by A = $\pi r^{2}$cm = $\frac{22}{7} (\frac{21}{2})^{2}$ =$\frac{22}{7} * \frac{21}{2} * \frac{21}{2} in^{2}$ =$\frac{33 * 21}{2} in^{2}$ = 346$\frac{1}{2} in^{2}$

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