Give a quick stream of consciousness before answering the following question. Find the mean proportional between 64 & 81?
Options:
(A) A) 59
(B) B) 61
(C) C) 63
(D) D) 72
(E) E) 67
Formula = ab
A = 64 and B = 81
6481 = 8 9 = 72
The answer: (D).