The Formula for the Area of a Circle Is $\mathrm { A } = \pi r ^ { 2 }$

question 92

Multiple Choice

The formula for the area of a circle is $\mathrm { A } = \pi r ^ { 2 }$ , where $r$ is the radius. Solve the formula for $r$ , and use your answer to find the radius of a circle with area 25 feet. Use $3.14$ for $\pi$ and round the answer to the nearest tenth of a foot.

• A) \(r = \frac { A } { 2 \pi } ; 4.0\) feet
• B) \(r = \sqrt { A - \pi } ; 4.7\) feet
• C) \(r = \sqrt { \frac { A } { \pi } } , r = - \sqrt { \frac { A } { \pi } } ; 2.8\) feet or \(- 2.8\) feet
• D) \(r = \sqrt { \frac { A } { \pi } } ; 2.8\) feet

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