Question

What is the exact area of a circle with a diameter of 37 inches?

Answer 1

Remember this:
\[A=\pi r^2\]
r is half the diameter

Answer 2

\(A=\pi r^2=\pi \frac{d^2}{4}\)

Answer 3

You have already posted this question earlier here: http://openstudy.com/updates/500ad2fae4b0549a892f282f
where @maheshmeghwal9 helped you out.