Answer:
Explanation:
Let the radius be r
UV is tangent to the circle T which means UV is perpendicular to UT, that makes ΔUVT a right-angled triangle.
Which means:
∠TUV = 90°
So, We can use pythagoras theorem to find the radius of the circle.
In the Δ:
Hypotenuse = r + 9
Base = r
Perpendicular = 12
Pythagoras Theorem:
(Hypotenuse)² = (Base)² + (Perpendicular)²
(6 + r)² = (r)² + (22)²
(6)² + 2(6)(r) + (r)² = r² + 484
36 + 12r + r² = r² + 484
Subtract r² to both sides
36 + 12r = 484
Subtract 36 to both sides
12r = 484 - 36
12r = 448
Divide both sides by 12
r = 448/12
r = 37 mm