Trapezoid – Definition with Examples

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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:

non example of trapezoid - SplashLearn

Non-Examples:

six sided figure - SplashLearn
three sided figure with. no parallel sides - SplashLearn
(A) It is not a trapezoid because it is a 6-sided figure.(B) It is not a trapezoid because it is a 3-sided figure with no parallel sides.
curved figure - SplashLearn
parallel sides - SplashLearn
(C) It is not a trapezoid because it is a curved figure.(D) It is not a trapezoid because it has rounded corners and 2 pairs of parallel sides.

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

Median of Trapezoid

A median of a trapezoid is the line segment joining the midpoints of the two non-parallel sides of a trapezoid.

The median of a trapezoid is parallel to the set of parallel lines.

Median of trapezoid - SplashLearn

Median = $\frac{BC+AD}{2}$ = $\frac{a+b}{2}$

Properties of a Trapezoid

  • The bases are parallel to each other.
  • The median is parallel to both the bases and its length will be the average of the length of the bases.
  • Sum of all the angles in a trapezoid is equal to 360°.
  • The sum of the angles on the same side is equal to 180°.

Area of Trapezoid

Area of a trapezoid = $\frac{1}{2}$ × (sum of parallel sides) × (distance between them)

Area of trapezoid - SplashLearn

Let ABCD be a trapezoid in which AB is parallel to DC and let h be the height.

Area = $\left\{\frac{1}{2}\times (AB + BC)\times h \right\}$

= $\left\{\frac{1}{2}\times (a + b)\times h \right\}$

Perimeter of Trapezoid

The perimeter of a trapezoid is the sum of all its sides.

Therefore, for the trapezoid shown above with sides AB, BC, CD and DA, the perimeter can be written as

Perimeter = AB + BC + CD + DA

Real Life Examples

We can find trapezoids in many real-life objects For example a lamp, popcorn box, handbag, and so on.

perimeter of trapezoid - SplashLearn

Solved Examples on Trapezoid:

Example 1: Fill in the blanks.

  1. The trapezoid having non-parallel sides equal is known as ______________.
  2. _____________ trapezoid has a pair of adjacent angles equal to 90°.
  3. Neither the sides nor the angles of _______________ trapezoid are equal.

Solution:

  1. isosceles trapezoid
  2. Right
  3. scalene

Example 2: Find the length of median PQ of given trapezoid.

length of median - SplashLearn

Solution:

Median = $\frac{1}{2}\times (\text{sum of the basis}) = \frac{AD + BC}{2} = \frac{8 + 30}{2} cm = 19 cm$

Example 3: Find the perimeter of a given trapezoid.

perimeter of trapezoid example - SplashLearn

Solution:

Perimeter = PQ + QR + RS + SP = (15 + 6 + 20 + 5) cm = 46 cm

Example 4: Find the area of a given trapezoid.

area of given trapezoid - SplashLearn

Solution:

Area = $\frac{1}{2}\times (\text{sum of parallel sides})\times (\text{altitude})$

= $\frac{1}{2}\times (7 + 11)\times 6$ sq.cm

= $\frac{1}{2}\times 18\times 6 sq.cm$

= 54 sq.cm

Practice Problems

Trapezoid

Attend this Quiz & Test your knowledge.

1The altitude refers to what measurement of a trapezoid?

Heigh
Width
Angle
Diagonal
CorrectIncorrect
Correct answer is: Heigh
The height of the trapezoid is referred to as it's altitude.

2How many right angles are there in the right trapezoid?

One
Two
Three
Four
CorrectIncorrect
Correct answer is: Two
A right trapezoid is a trapezium with a pair of right angles.

3What is the difference between trapezoid and parallelogram?

Trapezoid has 2 pairs of parallel sides, and parallelogram has 1 pair of parallel sides.
Trapezoid has 1 pair of parallel sides and parallelogram has 2 pairs of parallel sides.
Trapezoid has 2 sides and parallelogram has 4 sides.
Trapezoid has 4 equal angles and parallelogram has all 4 unequal angles.
CorrectIncorrect
Correct answer is: Trapezoid has 1 pair of parallel sides and parallelogram has 2 pairs of parallel sides.
Trapezoid has 1 pair of parallel sides and parallelogram has 2 pairs of parallel sides. Both trapezoid and parallelogram are quadrilaterals. The difference lies in the number of parallel sides they have.

4What do we call sides which are not parallel in a trapezoid?

Diagonals of trapezoid
Bases of trapezoid
Legs of trapezoid
Altitudes of trapezoid
CorrectIncorrect
Correct answer is: Legs of trapezoid
The two parallel sides of the trapezoid are referred to as the bases of the trapezoid; the other two sides are called the legs of the trapezoid.

Frequently Asked Questions

Since, trapezoids are closed figures with 4 sides so we can call them as quadrilaterals as well.

By definition both trapezoid and trapezium are quadrilaterals with one pair of parallel sides. But, trapezoid is according to the US English and trapezium is according to the UK  English.

No, a trapezoid can have either 2 right angles or no right angles at all.

No, a trapezoid is a quadrilateral with only one pair of parallel sides whereas a rhombus has 2 pairs of parallel sides and all of them equal to each other. 

No, a trapezoid cannot be a parallelogram. Trapezoid has only one pair of parallel sides while in a parallelogram there are two pairs of parallel sides.


Trapezoid – Definition with Examples

Shapes

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Trapezoid – Definition with Examples

Angles

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Trapezoid – Definition with Examples

Parallel and Perpendicular Lines

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