Question

The number of sides of a polygon which has 27 diagonals.​

Answer 1

Answer:

no of diagonals= n(n-3)/2

27=n^2-3n/2

54=n^2-3n

n^2-3n-54

n^2-9n+6n-54

n(n-9)+6(n-9)

(n-9)(n+6)

n=9,-6 -6 is not possible so 9 is the answer.

hope it helps..

Answer 2

→Question: The number of sides of a polygon which has 27 diagonals.​

↔Given: Number of diagonals in a polygon = 27

↔To find: Number of sides

→Solution:

⇒Number of diagonals = n(n-3)/2

⇒27=n^2-3n/2

54=n^2-3n

n^2-3n-54

n^2-9n+6n-54

n(n-9)+6(n-9)

(n-9)(n+6)

∴n=9,-6 -6 is not possible ( as negative ) , so 9 is the answer.