Question

What is the equation of a circle with center (2,-5) and
radius 4?

Answer 1

Choice C

Explanation:

The Equation of a circle is (x-h)^2+(y-k)^2=r^2, where h and k are the x and y coordinates respectively of the center of the circle, and r is the radius. Because the center here is (2, -5), we have (x-2)^2+(y- - 5)^2, and the two minuses become (y+5)^2. This eliminates A and B. The radius is 4, so r^2=16, and thus, we get C.