A polygon has 44 diagonals, then the number of its sides are	Pick one:
A) 11	B) 9	C) 7	D) 5	E) 3

Rationale: let the number of sides be n . the number of diagonals is given by nc 2 - n therefore , nc 2 - n = 44 , n > 0 n ( n - 1 ) / 2 - n = 44 n 2 - 3 n - 88 = 0 n 2 - 11 n + 8 n - 88 = 0 n ( n - 11 ) + 8 ( n - 11 ) = 0 n = - 8 or n = 11 . answer : a
Answer: A