Answer:
16 ft
Explanation:
If you connect points A and C with a straight line, you will have a right triangle with hypotenuse AC (radius), shorter leg 1/2 of CD and the longer leg 1/2 of AB.
AC = radius = 10 ft
1/2 CD = 1/2 of 12 = 6 ft
So we can use Pythagoras' Theorem to find the length of the longer leg of the right triangle:
6² + b² = 10²
36 + b² = 100
b² = 100 - 36
b² = 64
b = √64 = 8
As b = 1/2 AB, then AB = 2 x b = 2 x 8 = 16 ft