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Question: Answered & Verified by Expert
A polygon has 54 diagonals. The number of sides of this polygon is
MathematicsPermutation CombinationAP EAMCETAP EAMCET 2020 (18 Sep Shift 1)
Options:
  • A 12
  • B 15
  • C 16
  • D 9
Solution:
1279 Upvotes Verified Answer
The correct answer is: 12
Let number of sides of the polygon is \(n\), then number of diagonals is
\(\begin{aligned}
\frac{n(n-3)}{2} & =54 \quad \text{(given)} \\
\Rightarrow \quad n(n-3) & =108 \quad \Rightarrow n=12
\end{aligned}\)

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