Problema Solution
The formula below yields the number of diagonals, D, in a polygon of n sides. Find the number of sides of a polygon that has 405 diagonals.
D = (n(n-3))/2
Answer provided by our tutors
D = 405 diagonals and we need to find n
D = (n(n-3))/2 that is
(n(n-3))/2 = 405
by simplifying and solving the above equation we get
click here to see the step by step solution of the equation
n = 30 sides
we consider the positive solutions of the equation only since n>0 thus
the polygon that has 405 diagonals has 30 sides.