EXPLANATION
We can apply the Pythagorean Theorem as shown as follows:
If the radius is 20 ft, then c=20 ft
If CD = 32 ft, then b= CD/2 = 32/2 = 16 ft
Replacing terms:
Isolating a:
Computing the powers:
Applying the square root to both sides:
Simplifying:
The measure of AB is 12*2= 24 ft long