Answer:
x = 3
Explanation:
Given a tangent and a secant from an external point to the circle, then
The square of the tangent is equal to the product of the secant's external part and the entire secant, that is
8(8 + 2x + 4) = 12²
8(12 + 2x) = 144 ( divide both sides by 8 )
12 + 2x = 18 ( subtract 12 from both sides )
2x = 6 ( divide both sides by 2 )
x = 3