The number of ways of choosing three vertices fromseven vertices of a regular heptagon such that they form an isosceles triangle, is

Three vertices are chosen randomly from the seven vertices of a regular 7 -sided polygon. The probability that they form the vertices of an isosceles triangle is

Three vertices are chosen randomly from the seven vertices of a regular 7 -sided polygon. The probability that they form the vertices of an isosceles triangle is

Three vertices are chosen randomly from the seven vertices of a regular 7 -sided polygon. The probability that they form the vertices of an isosceles triangle is

Three vertices are chosen randomly from the seven vertices of a regular 7 -sided polygon. The probability that they form the vertices of an isosceles triangle is

Three vertices are chosen randomly from the seven vertices of a regular 7-sided polygon. The probability that they from the vertices of an isosceles triangle is-

Three vertices are chosen from the vertices of a regular hexagon,then the probability that they will form an equilateral triangle is

Find the number of diagonals formed by joining the vertices of the regular hexagon.

If three vertices of a regular hexagon are chosen at random, then the chance that they form an equilateral triangle is :

The number of triangles that can be formed using the vertices of a 20 sided regular polygon such that the triangle and the polygon does not have any side common is