1. Draw a sketch!

2. Let P(x, y) denote a point whose distance to Q(8, 8) equals the tangent segment to the given circle. The you know that the distance d can be calculated by:

3. The distance d, the radius r of the circle and the distance of P to the center of the circle form a right triangle:

4. Plug in r = 4 and dē from the 1st equation into the 2nd equation:

Solve for y.