Types of Quadrilaterals

Trapezium

One pair of parallel sides

AB ∥ CD

Parallelogram

Opposite sides are parallel

• AB ∥ CD
• AD ∥ BC

 Opposite sides are equal

• AB = CD
• AD = BC

Rhombus

Parallelogram with all sides equal

So,

• AB ∥ CD & AD ∥ BC
• AB = BC = CD = AD

Rectangle

Parallelogram with opposite sides equal & all 4 angles 90°

So,

• AB ∥ CD & AD ∥ BC
• AB = CD & AD = BC
• ∠A = ∠B = ∠C = ∠D = 90°

Square

Parallelogram with all sides equal & all 4 angles 90°

So,

• AB ∥ CD & AD ∥ BC
• AB = BC = CD = AD
• ∠A = ∠B = ∠C = ∠D = 90°