1. The problem is to find the equation of a circle given its center and radius. 2. The general formula for a circle with center $(h, k)$ and radius $r$ is: $$ (x - h)^2 + (y - k)^2 = r^2 $$ 3. Here, the center is given as $(2, 3)$ and the radius is $4$ units. 4. Substitute $h = 2$, $k = 3$, and $r = 4$ into the formula: $$ (x - 2)^2 + (y - 3)^2 = 4^2 $$ 5. Simplify the right side: $$ (x - 2)^2 + (y - 3)^2 = 16 $$ 6. This is the equation of the circle. Final answer: $$ (x - 2)^2 + (y - 3)^2 = 16 $$