A polygon has 12 vertices lying on a circle. Find the number of diagonals.

A polygon has 90 diagonals . Find the number of its sides ?

A polygon has 90 diagonals. Find the number of its sides ?

A regular polygon of 10 sides is constructed. Triangles are formed joining vertices of the polygon. Find the number of triangles (i) if two sides of trinangle coincide with the sides of polygon. (ii) if only one side of triangle coincide with the side of polygon.

Prove that the area of a regular polygon hawing 2n sides, inscribed in a circle, is the geometric mean of the areas of the inscribed and circumscribed polygons of n sides.

The number of diagonals of a decagon:

A polygon has 77 diagonals. The number of sides of the polygon is

The interior angles of a regular polygon measure 150^@ each. The number of diagonals of the polygon is

When a particle is moving in vertical circle

The ratio of the area of a regular polygon of n sides inscribed in a circle to that of the polygon of same number of sides circumscribing the same is 3:4. Then the value of n is