Question

center is (13, -13) and radius is 4

Answer 1

The equation of a circle can be thought of as the set of points which are 4 units away from the point (13,-13). That means they will solve the Pythagorean identity: \(a^2+b^2=c^2\) if you think of a as the distance on the x-axis from 13; b as the distance on the y-axis from -13; and c as the radius.