Common Core Math Vocabulary

Trapezoid - Definition with Examples

What is Trapezoid?

A trapezoid, also known as a trapezium, is a flat closed shape having 4 straight sides, with one pair of parallel sides. 

The parallel sides of a trapezium are known as the bases, and its non-parallel sides are called legs. A trapezium can also have parallel legs. The parallel sides can be horizontal, vertical or slanting. 

The perpendicular distance between the parallel sides is called the altitude. 

trapezoid

 

Examples:

example of trapezoid

Non-Examples:

non-example of trapezoid

 

Types of trapezoid

Trapezoid is of three types namely

1. Right trapezoid: It has a pair of right angles.

right trapezoid

2. Isosceles trapezoid: It has equal length of non-parallel sides. In the image, sides, AD and BC are equal.

isosceles trapezoid

3. Scalene trapezoid: It neither has equal angles nor has equal sides.

scalene trapezoid

 

Properties of a trapezoid

  • A trapezoid is a parallelogram if both pairs of its opposite sides are parallel.

  • A trapezoid is a square if both pairs of its opposite sides are parallel; all its sides are of equal length and at right angles to each other.

  • A trapezoid can be a rectangle if both pairs of its opposite sides are parallel; its opposite sides are of equal length and are at right angles to each other.

 

Real life Examples

A few out of many trapezoid examples are the face of a popcorn box, handbag, and bridges.

real life example of trapezoid

 

  Fun Facts

  • Trapezoid was known as τραπέζιον ‘trapézion’ in Ancient Greek which literally means “a little table” and also refers to “irregular quadrilateral”. Also, ‘oid’ in Ancient Greek means “resembling”.

  • The word trapezium was introduced in the English language in1570. Marinus Proclus was the first person to use the word trapezoid in the first book of Euclid’s Elements. 

 

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