Solve the problem.
-The area of a circle with radius $\mathrm { r }$ is given by the function $\mathrm { A } ( \mathrm { r } ) = \pi \mathrm { r } ^ { 2 }$. Find the area of the base of a circular storage tank if the radius is 4 feet long. Use $\pi = 3.14$.
A) $25.12$ square feet
B) $12.56$ square feet
C) $50.24$ square feet
D) 48 square feet

Question

Quizplus · Accepted Answer

Substitute 4 for $ \mathrm { r } $ in the function: 
$$\mathrm { A } (4) = \pi (4)^2 = 16\pi $$
Using the approximation $\pi = 3.14$, we have 
$$\mathrm { A } (4) \approx 16 \times 3.14 \approx 50.24 $$
Therefore, the answer is C: $50.24$ square feet.

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