If a polygon has 8 sides, then the number of diagonals of the polygon is _____.

If a polygon has 6 sides, then the number of diagonals of the polygon is _______

A regular polygon has 20 sides. Find the number of diagonals of the polygon.

In a polygon,no three diagonals are concurrent.If the total number of points of intersection of diagonals interior to the polygon is 70 ,then the number of diagonals of the polygon is a.20 b.28 c.8 d.none of these

If each interior angle of a regular polygon is 135^@ , then the number of diagonals of the polygon is equal to

Number of diagonal of an n-sided polygon is__________

Find the number of diagonals of a polygon of 10 sides.

Write the number of diagonals of an n-sided polygon.

Find the numbers of diagonals in the polygon of n sides.