Quadrilaterals
A quadrilateral is a polygon with four sides.
A quadrilateral has two diagonals.
The sum of the interior angles of a quadrilateral equals 360º.
Types of Quadrilaterals
Parallelograms
A parallelogram is a quadrilateral which has parallel sides in pairs. They are classified as follows:
Square
A square has 4 equal sides and 4 right angles.
Rectangle
A rectangle has equal opposite sides and 4 right angles.

Rhombus
A rhombus has four equal sides and equal opposite angles.

Rhomboid
A rhomboid has opposite sides that are parallel and equal.

Trapezoid
Trapezoids are quadrilaterals with only two parallel sides. They are classified as follows:
Right Trapezoid
A right trapezoid has two right angles.

Isosceles Trapezoid
An isosceles trapezoid has two of its non-parallel sides equal in length.

Scalene trapezoid
A scalene trapezoid doesn´t have equal sides or angles.
