A circle centred at ($7$7, $-8$−8) has an $x$x-intercept at ($-10$−10, $0$0). Find the exact radius of the circle.

Consider the circle with equation $\left(x-0.7\right)^2+\left(y+4.4\right)^2=3$(x−0.7)2+(y+4.4)2=3.

Consider the circle with equation $\left(x+3.1\right)^2+\left(y-\frac{3}{2}\right)^2=\frac{9}{16}$(x+3.1)2+(y−32)2=916.

Consider the circle with equation $\left(x-8\right)^2+\left(y+1\right)^2=13$(x−8)2+(y+1)2=13.