The region of the plane that lies inside the curve is called the interior of the curve.

A polygon in which at least one interior angle is greater than 180° is called convex polygon.

6 sided polygon is called hexagon.

Sum of all interior angles of a quadrilateral is 180°

Each interior angle of a n-sided regular polygon is [(2n−4)×90]/n

The diagonals of a parallelogram bisect each other at right angles.

The opposite angles of a parallelogram are of equal measure.

The diagonals of a rhombus bisect the angles of a rhombus.

The diagonals of a square are not equal.

Co-interior angles of a parallelogram are supplementary.

The diagonals of a kite bisect at right angles.

All rectangles are squares.

All rhombuses are parallelograms.

All squares are rhombuses and also rectangles.

All squares are not parallelograms.

All kites are rhombuses.

All rhombuses are kites.

All parallelograms are trapeziums.

All squares are trapeziums.