Answer:
x = 3
Explanation:
The Pythagorean theorem tells you the sum of squares of the legs is equal to the square of the hypotenuse. In this geometry, a radius from the circle center to point T is length x, and is one leg of the right triangle.
x^2 +4^2 = (x +2)^2
x^2 +16 = x^2 +4x +4 . . . . . expand
12 = 4x . . . . . . . . . . . . . subtract (x^2 +4)
3 = x . . . . . . . divide by 4
The radius of the circle is 3 cm.