The center of a circle is ( -3, 0). The circle passes through the point (-4, -1). What is it’s radius? Please help me out!

You need to use Pythagoras’ Theorem. 
A² + B² = c² and c is the hypotenuse of the right angled triangle.

The height of the tower (5 feet) is A and the distance from the end of the cable and the base of the tower (12 feet) is B. The length of ONE cable is c. So:

A² + B² = c²
5² + 12² = c²
25 + 144 = c²
169 = c²
13 = c. This is the length of one cable.

3 x 13 = 39 therefore the total length of the cables is 39 feet.

25