Try to find the number of corners in a rectangle.

Draw a triangle and try to count corner points and line segments.

Think of any quadrilateral and find out the number of corner points and line segments.

Think of the definition of different terms which are related to circle.

Try to recall the names of components of circle.

Take out pencil and mark each vertex while counting them.

Use the relation between radius and diameter of a circle.

Try to find the relation of diameter to any of the folllowing options.

Think of the definition of diameter of a circle.

Use the relation between radius and diameter of a circle.