In a circle with a radius of 6, what is the area of the biggest rectangle that can be cut out of this circle ?
Choose the correct choice from the following answers:
A) 12
B) 96
C) 50
D) 72
E) 144

Rationale: the biggest rectangle would be a square , whose diagonal is 12 ( 6 + 6 ) if side of square is a , 144 = a ^ 2 + a ^ 2 = 2 a ^ 2 so area of square = a ^ 2 = 144 / 2 = 72 answer : d
Answer: D