Question

The formula for the number of diagonals in
a polygon of n sides is d=1/2[n(n-3)].
If
the number of diagonals in a polygon is
twice as many as the number of sides,
what is the number of sides:

Answer 1

the answer can be:_
7 heptagon
as 1/2 (7 (7-3))
=14 which is twice the number of sides