Answer:
x=6.9 inches
Explanation:
If a tangent and a secant are draw to a circle from the same exterior point, the square of the length of the tangent is equal to the product of the total length of the secant and the length of the external segment of the secant.
From the given diagram,
(8+4)×4=x²
12×4=x²
x²=48
x=6.9 inches