The area of a pizza is 1386 centimeters. what is the radius?

Assuming that this is a circular pizza :P

The area of a circle is:

A=πr^2  divide both sides by π

A/π=r^2  take the square root of both sides

r=√(A/π), we are told that A=1386 so:

r=√(1386/π) cm

r≈21 cm  (to nearest hundredth of a centimeter)