Part A. Calvin is using the formula A=3r^2 to estimate the area of a circle
Solve the formula for r?
Part B. Use your equation to estimate the radius of a circle with an approximate area of 300 cm^2
already did the first one for you.
so, what's the problem with using the formula? Just plug in your number for r!
with r = 300, A = 3 * 300^2 = 3 * 90000 = 279,000 cm^2
I think I'd rather do r = 3m, so
A = 27 m^2