There are six types of quadrilaterals and these quadrilaterals can be classified by the relationships of their sides and angles.
• Parallelogram
• Rectangle
• Square
• Rhombus
• Trapezoid
• Kite

## How to identify a parallelogram

A parallelogram is a four-sided polygon with two pairs of parallel and equal sides. The following figure is a parallelogram.

In a parallelogram, all the followings are true:

• Opposite sides are parallel (AB || DC and AD || BC)
• Opposite sides are equal (AB = DC and AD = BC )
• Opposite angles are equal (angle A = angle C and angle B = angle D)

## How to identify a rectangle

A rectangle is a parallelogram with 4 right angles. The following figure is a rectangle.

In a rectangle, all the followings are true:

• Opposite sides are parallel (HG || EF and HE || GF)
• Opposite sides are equal (HG = EF and HE = GF)
• All four angles are equal to 90 degrees ( angle E = angle F =  angle G = angle H = 90 degrees)

## How to identify a square

A square is a rectangle with 4 equal sides.The following figure is square.

In a square, all the followings are true:

• Opposite sides are parallel (JK || IL and JI || KL)
• All four sides are equal (JI = KL = JK = IL)
• All four angles are equal to 90 degrees ( angle I = angle J =  angle K = angle L = 90 degrees)
Rhombus: A rhombus is a parallelogram with 4 equal sides. The following figure is a rhombus.

In a rhombus, all the followings are true:

• Opposite sides are parallel (PO || MN and PM || ON )
• All four sides are equal (PO = ON = NM = MP )
• Opposites angles are equal ( angle M = angle O and angle N = angle P)

## How to identify a trapezoid

Trapezoid: A trapezoid is a quadrilateral with only one pair of parallel sides. There are three types of trapezoids.

Scalene trapezoid: A scalene trapezoid is a trapezoid with no equal sides.The following is a scalene trapezoid.

Right-angled trapezoid: A right-angled trapezoid is a trapezoid with two right angles. The following is a right-angle trapezoid.

Isosceles trapezoid: In an isosceles trapezoid, non-parallel sides are equal. The following is an isosceles trapezoid.

## How to identify a kite

A kite is a quadrilateral with two pairs of adjacent sides that are equal. Furthermore, no opposite sides are equal.

## Types of quadrilaterals quiz. Take the quick to check if you understand this lesson.

100 Tough Algebra Word Problems.

If you can solve these problems with no help, you must be a genius!

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