Which of the following (there may be more than one) represent a formula you could use to find the area of a circle?


A\ =\ \pi d
A = πd



A\ =\ \pi\left(r\right)\left(r\right)
A = π(r)(r)



A\ =\ \pi\left(r\right)\left(2\right)
A = π(r)(2)



A\ =\ \pi r^2
A = πr
2