Acircle has a diameter with endpoints of (-3, 8) and (7, 4). what is the center of the circle?

(2, 6) because it is halfway between both endpoints

The center will be in the direct midpoint of the two points. 

So, the formula for midpoint is (X1+X2)/2, (Y1+Y2)/2

Our X points are -3 and 7. So, we do -3+7/2, which is 2

Our Y points are 8 and 4. So, we do 8+4/2, which is 6

Put it into the form of a point, and we get (2,6) as the center of the circle.