Permutations Practice Test 2

Question : 1 of 30

Marks: +1, -0

A polygon has 44 diagonals, then the number of its side are:

Solution:

If n is the number of sides, then the no. of diagonals

= ^nC_2 - n = 44

1/2n(n-1)-n=44

⇒ (n - 11) (n + 8) = 0

⇒ n = 11

(∵n ≠ - 8)

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