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[show]**What is a quadrilateral?**Edit

Quadrilateral just means "four sides", (*quad* means four, *lateral *means side).

**Properties of a quadrilateral**Edit

- Four sides (or edges)

- Four vertices (or corners).

- The interior angles add up to
**360 degrees**:

**Types of quadrilateral and their properties**Edit

**The Rectangle**Edit

**The Rectangle**

A rectangle is a four-sided shape where every angle is a right angle (90°).

Also **opposite sides** are parallel and of equal length.

Edit

Properties:

Opposite sides are parallel

Opposite sides are equal.

All four angles are right angle.

Ø Diagonal bisect each other.

Ø Diagonals are equal in length.

Ø Two pairs of congruent triangle are formed by the diagonal.

**The Rhombus**Edit

**The Rhombus**

A rhombus is a four-sided shape where all sides have equal length.

Ø Also opposite sides are parallel.

Ø Opposite angles are equal.

Ø All four sides are equal.

Ø Four congruent triangles are formed by the diagonals.

Ø Diagonals bisect the angles at the vertices.

Ø The diagonals (dashed lines in second figure) of a rhombus bisect each other at right angles.

**The Square**Edit

**The Square**

A square has equal sides and every angle is a right angle (90°)

Ø Also opposite sides are parallel.

Ø Four congruent triangles are formed by diagonals.

Ø Diagonal bisect each other at right angle.

Ø All four sides are equal.

Ø All four angles are right angle.

Ø Diagonals are equal in length.

Ø Diagonals bisect the angles at the vertices. Hence each angle is equal to 45 degree.

**The Parallelogram**Edit

A parallelogram's opposite sides are parallel and equal in length. Also opposite angles are equal (angles "a" are the same, and angles "b" are the same)

**NOTE:** Squares, Rectangles and Rhombuses are all Parallelogram

Properties:

Ø Opposite sides are parallel.

Ø Diagonal bisect each other.

Ø Two pairs of congruent triangles are formed by diagonal.

Ø Diagonal bisect each other.

Ø Opposite angles are equal.

**The Trapezium**Edit

**The Trapezium**

A trapezium (called a trapezium in the UK) has a pair of opposite sides parallel.

It is called an **isosceles** trapezium if the sides that aren't parallel are equal in length and both angles coming from a parallel side are equal, as shown.

A **trapezium** (UK: trapezoid) is a quadrilateral with NO parallel sides.

Properties of trapezium:

Ø Only one pair of opposite sides parallel.

Property of isosceles trapezium:

Ø One pair of opposite side parallel.

Ø Pair of non-parallel sides is equal.

Ø Two pairs of equal adjacent angles.

**The kite**Edit

**The kite**

Properties:

It has two pairs of sides.

Ø Each pair is made up of adjacent sides that are equal in length.

Ø The angles are equal where the pairs meet.

Ø Diagonals (dashed lines) meet at a right angle, and one of the diagonal bisects (cuts equally in half) the other.