A circle is drawn on the coordinate plane. It has a center at (2, 1) and passes through the point (2, 5). What is the approximate circumference of the circle?
First we need to find the radius. Using Pythagorean theorem we can find the radius which is the distance between the center and any point along the circle:
r=((5-1)^2+(2-2)^2)^(1/2)
r=(4^2-0^2)^(1/2)
r=4 units.
Circumference=2pr so our circumference is 8p units^2
