Answer:
a) UT² = ST · (RS + ST)
b) UT = 6 in
Step-by-step explanation:
- Secant : a line that intersects the circle at two points
- Tangent : a line that touches the circle at one point
If a secant and a tangent of a circle are drawn from a point outside the circle, then the product of the lengths of the secant and its external segment equals the square of the length of the tangent segment.
UT² = ST · (RS + ST)
Given:
- RS + ST = RT
⇒ RS + 4 = 9
⇒ RS = 5
Using: UT² = ST · (RS + ST)
⇒ UT² = 4(5 + 4)
⇒ UT² = 36
⇒ UT = √36 = 6 in