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In a polygon the number of diagonals 77....

In a polygon the number of diagonals 77. Find the number of sides of the polygon.

Text Solution

Verified by Experts

Let number of sides of the polygon`=n`, then `.^(n)C_(2)-n=77`
`implies(n(n-1))/(2)-n=77implies(n(n-3))/(2)=(14xx11)/(2)`
we get, `n=14`
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