The equation is: 0.5*(n2-3n) = diagonals whereas n is the number of sides of the polygon
A 7 sided polygon has 14 diagonals
11
There can be 14 lines in a seven side shape * * * * * That is the total number of diagonals from ALL vertices. Not what the question asked, though. From one vertex, there can be 4. One to every other vertex except for itself and one each on either side.
The equation is S=L where S = number of sides and L = lines of symmetry.
They are equal.
The number of triangles formed by the diagonals of a 21 sided polygon is C(21,3) = 21x20x19/3x2x1 = 1,330.
65
The five sided Polygon has 5 diagonals
A 7 sided polygon has 14 diagonals
It is: 0.5*(n2-3n) = diagonals whereas n is the number of sides of the polygon
The formula is: 0.5*(n2-3n) = diagonals whereas n is the number of sides of the polygon
Number of diagonals = 1/2*(n2-3n) where n = the number of sides of the polygon.
A polygon with 14 diagonals will have 7 sides
1/2*(n2-3n) = number of diagonals Rearranging the formula: n2-3n-(2*diagonals) = 0 Solve as a quadratic equation and taking the positive value of n as the number of sides.
By using the polygon diagonal formula or the quadratic equation formula in which in both formulae they work out that the polygon in question has 21 sides.
It has 20 diagonals
14 diagonals