Solve for x.
Solve for x.

Answer:
20
Step-by-step explanation:
x is the radius of the circle. The tangent line is perpendicular to the radius line at that point. Using Pythagorean theorem:
x² + 15² = (x + 5)²
x² + 225 = x² + 10x + 25
225 = 10x + 25
200 = 10x
x = 20