Quadrilaterals

A quadrilateral is a polygon having 4 sides. ABCD is a quadrilateral and AC and BD are its diagonals.

Special quadrilaterals

Parallelogram

A parallelogram has its opposite pairs of sides parallel. Its other properties are:

(i) The opposite sides are equal.

(ii) The opposite angles are equal.

(iii) The diagonals bisect each other.

In the figure above, the perpendicular AL to DC has been drawn. AL is called the height of ABCD.

Rectangle

A rectangle is a parallelogram having all angles equal.

Its other properties are:

(i) The diagonals are equal.

(ii) Each angle is a right angle.

Rhombus

A rhombus is a parallelogram having all sides equal.

Its other properties are:

(i) The diagonals bisect each other at right angles.

(ii) The diagonals bisect the angles at each vertex.

Square

A square is a parallelogram having all its sides equal and all its angles equal.

Its other properties are:

(i) The diagonals bisect each other at right angles and are equal.

(ii) The diagonals bisect the angles at each vertex and each half is equal to 45^o.

Trapezium

A trapezium is a quadrilateral having one pair of opposite sides parallel.

A trapezium with non-parallel sides equal is called an isosceles trapezium.

Kite

A kite is a quadrilateral having both pairs of adjacent sides equal.

Its other properties are:

(i) One diagonal bisects the other diagonal at right angles.

The above properties are tabulated below:

* Yes in Isosceles Trapezium