WBJEE · Maths · Permutation Combination
A polygon has 44 diagonals. The number of its sides is
- A 10
- B 11
- C 12
- D 13
Answer & Solution
Correct Answer
(B) 11
Step-by-step Solution
Detailed explanation
Hints: \({ }^n \mathrm{C}_2-n=44\) \[ \begin{aligned} & \frac{n(n-1)}{2}-n=44 \\ & n\left[\frac{n-1}{2}-1\right]=44 \\ & n(n-3)=88 \\ & n(n-3)=11 \times 8 \\ & n=11 \end{aligned} \]
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