Question

An equation of a circle is given as (x + 6)² + (y − 7)² = 81. Find the center and radius of the circle. Show all work to receive full credit.

Answer 1

Center is (-6,7) and radius is 9. A circle with a center at (h,k) and a radius of r has the equation (x-h)^2 + (y-k)^2=r^2 so h= -6 k= 7 r is 9 you just work back wards, what two numbers multiplied gives you 81? Well 9