Permutation and CombinationHard
Question
If in a regular polygon the number of diagonals is 54, then the number of sides of this polygon is :
Options
A.12
B.6
C.10
D.9
Solution
Number of diagonal = 54
= 54
n2 − 3n − 108 = 0
⇒ n = 12
= 54n2 − 3n − 108 = 0
⇒ n = 12
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