Which number should replace both the asterisks in (* /20) x (*/180) = 1 ?  Choices:
A) 20  B) 40  C) 60  D) 90  E) 120

Rationale: "let ( y / 20 ) x ( y / 180 ) = 1 y ^ 2 = 20 x 180 = 20 x 20 x 9 y = ( 20 x 3 ) = 60 the answer is c ."
Answer: C