Answer:
x = 8
Step-by-step explanation:
Theorem
When a secant segment and a tangent segment meet at an exterior point, the square of the measure of the tangent segment is equal to the product of the measures of the secant segment and its external secant segment.
Secant: a straight line that intersects a circle at two points
Tangent: a straight line that touches a circle at only one point
Given:
- tangent segment = x
- secant segment = 4 + 12 = 16
- external secant segment = 4
⇒ x² = 16 · 4
⇒ x² = 64
⇒ x² = √(64)
⇒ x = ±8
As distance is positive, x = 8
