Common Core Math Vocabulary

# Quadrilateral - Definition with Examples

Quadrilateral Definition: A quadrilateral is a closed 2-dimensional shape formed by joining 4 straight sides.

• A quadrilateral has 4 sides, 4 angles and 4 vertices.
• A quadrilateral can be regular or irregular.
• The sum of all the interior angles of a quadrilateral is 360 degree.

Quadrilaterals are classified by the number of pairs of parallel lines and by the number of equal sides.

#### Parallelogram:

A parallelogram is a quadrilateral with opposite sides parallel to each other. The opposite sides and angles of a parallelogram are equal.

#### Rectangle:

A rectangle is a quadrilateral with opposite sides parallel and of equal length. All angles of a rectangle are equal to 90 degrees.

#### Square:

A square is a special type of quadrilateral with all the sides equal and all the angles equal to 90 degrees.

#### Rhombus:

A rhombus is a special square which is slightly tilted at an angle. The opposite angles of a rhombus are equal. The diagonals of a rhombus intersect at the center at a right angle. They "bisect" (cut in half) each other at right angles.

### Properties of Quadrilaterals at a Glance

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