A circle is defined by the equation (x-5)² + (y+2)² = 49. What is the radius of the circle?

A circle with center $(h, k)$ and radius $r$ has the equation $(x - h)^2 + (y - k)^2 = r^2$. In $(x - 5)^2 + (y + 2)^2 = 49$, the right side is $r^2 = 49$, so $r = 7$, choice D. The center is $(5, -2)$. Choice A (49) is $r^2$, which needs a square root. Choice B ($-2$) is the $y$-coordinate of the center, and a radius cannot be negative. Choice C (5) is the $x$-coordinate of the center. The radius depends only on the right-hand side.