The area of the bottom of the pool would be 78.4602, but you can simplify to 78.46. Here's how it would be if you were to write it out:
A (area) = C2( C squared) over (this is a fraction) 4pi(4 times pi->3.14) = 31.4 2(31.4 squared) over (this is also a fraction) 4pi(4 times pi->once again; 3.14) = 78.4602 = 78.46.
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