AB is tangent to circle at B. Find x.

Answer:
x = 6
Step-by-step explanation:
using the Pythagorean theorem:
(4 + x)² = 8² + x²
16 + 8x + x² = 64 + x²
subtract x² and 16 from each side of the equation:
8x = 48
divide both sides by 8:
x = 6