What is the equation of the circle with a center at (4 ,-7 ) and a radius of 8 ?

1 Answer
Jan 26, 2016

(x-4)^2+(y+7)^2=64

Explanation:

The standard form of a circle with a center at (h,k) and a radius r is

(x-h)^2+(y-k)^2=r^2

Since the center is (4,-7) and the radius is 8, we know that

{(h=4),(k=-7),(r=8):}

Thus, the equation of the circle is

(x-4)^2+(y-(-7))^2=8^2

This simplifies to be

(x-4)^2+(y+7)^2=64