GRE Question of the Day (September 4)

The relationship between the area A of a circle and its circumference C is given by the formula \({A=kC^2}\), where k is a constant. What is the value of k ?

A. \({\frac{{1}}{{4\pi}}}\)

B. \({\frac{{1}}{{2\pi}}}\)

C. \({\frac{{1}}{{4}}}\)

D. \({2\pi}\)

E. \({4\pi^2}\)

Here \({\pi =3.14}\)