Question

a polygon with n sides has n(n-3)/2 diagonals.how many sides are there for a polygon with 104 diagonals?

Answer 1

Answer:

16 or 13

Step-by-step explanation:

Diagonals = n(n-3)/2

104 = n^2-3n/2

208 = n^2-3n

0 = n^2 - 3n - 208

0 = n^2 - 16n +13n - 208

0 = n(n-16) + 13(n-16)

0 = (n-16)(n-13)

Therefore, n = 16 ; n = 13