The center to circle would be the middle of the diameter. To find this, add the x values and the y values to get something like this: the x values are 2+6=8 and y values -8+4=-4. Then you will divide both of your answers by 2, so it would be 8/2 for the x-coordinate and -4/2 for the y-coordinate. This will give you (4,-2).
