math
posted by jenna .
what is the exact area of a circle with a diameter of 15 inches?

radius = 15/2
area = pi r^2 = pi (225/4) 
so its 225pi sq. in?

exact? One cannot write down exactly irrational numbers, such as PI.
The exact answer is 225/4 * PI 
pi r^2 = pi D^2/4 = area of circle