Trapezoid – Definition, Types, Properties, Examples, FAQs
reviewed by Jo-ann Caballes
Updated on January 6, 2026
Looking to improve your math knowledge? Brighterly is here to help!
As part of our knowledge base series on shapes, we’re exploring trapezoids today.
In this article, we’ll share the trapezoid meaning, the properties of trapezoid, different types of trapezoids, solved math problems and trapezoid practice problems.
What is a trapezoid?
A trapezoid (also called a trapezium) is a flat 2D shape with four straight sides. It consists of a top and bottom pair of parallel sides. Its parallel sides are called the bases, while its non-parallel sides are called the legs. And it’s also a type of quadrilateral. All trapezoid interior angles add up to 360°.
Trapezoid definitions: Inclusive vs exclusive
There are two types of trapezoid definition in geometry, exclusive and inclusive.
Exclusive definition
According to some, the trapezoid has only one pair of parallel sides, which means they aren’t parallelograms. This is known as the exclusive definition.
Inclusive definition
Others have the opinion, and this is the more popular one, that trapezoids can be a special kind of parallelogram because of their parallel sides. It is also known as the inclusive definition, which has been supported in higher education, especially the ‘taxonomy of quadrilaterals’ (which is an ordered group category of quadrilaterals).
This article will be using the inclusive definition of trapezoids shapes.
What makes a trapezoid?
A trapezoid makes a four-sided shape with exactly one pair of parallel sides, called the bases. The other two sides, called the legs, are non-parallel. This combination of parallel and non-parallel sides is what sets a trapezoid apart from other quadrilaterals like squares or rectangles.
Why definitions differ?
Different cultures have several variants of the definition of a trapezoid.
Parallel sides are called bases, and non-parallel sides are called legs. Parallel sides may be vertical, horizontal, or slanted. It is called the altitude when one base is located at a distance from another.
Types of trapezoid
Right trapezoid
A right-angled trapezoid is a trapezoid that has two right angles.
Isosceles trapezoid
This type of trapezoidal shape has non-parallel sides that have the same length.
Scalene trapezoid
A scalene trapezoid or non isosceles trapezoid has sides that are different lengths and non-congruent. This means each of its four angles is different. It also has a pair of parallel sides and a pair of non-parallel sides. It’s also known as a non-isosceles trapezoid.
Examples of trapezoids
Trapezoids might not be as obvious as circles or squares, but they’re all around us if you take a look. Let’s explore some trapezoid examples:
- Handbags — some of them have that classic trapezoid shape, with a narrower top and wider base.
- Staircases — take a look from the side, and some stairs form a perfect trapezoid silhouette.
- Lampshades — many of them sport a trapezoid shape, giving a cozy, angled glow.
- Bridges — certain bridge supports are trapezoid-shaped to spread out weight efficiently.
Midsegment of a trapezoid
The midsegment of a trapezoid is called the median. The median of a trapezoid is equal to half the sum of both its bases and parallel to them.
Properties of a trapezoid
The trapezoid properties make them different from other types of quadrilaterals. These properties of trapezoids are the main trapezoid attributes:
- An isosceles trapezoid has opposite sides of the same length.
- The median of trapezoids is parallel to both its bases.
- If both opposite sides are parallel, a trapezoid can also be a parallelogram.
- The top and bottom line (bases) of trapezoids shapes are parallel.
- A square can also be a trapezoid under the inclusive definition.
- A rectangle can also be a trapezoid under the inclusive definition.
- All trapezoid interior angles add up to 360°, and the angles on the same side add up to 180°.
Trapezoid formula
There are two trapezoid formulas you can use to calculate the area and perimeter of a trapezoid.
Area of trapezoid
The Area is the average of the two base lengths times the altitude
How to find the area of a trapezoid
This formula calculates the area of a trapezoid:
Area= ½ (A+B)h
(A = base1, B = base2, h = height).
Perimeter of trapezoid
To calculate the perimeter of a trapezoid, simply add all of its side lengths together.
If you don’t know all the side lengths, you can use the Pythagorean theorem to calculate them.
Solved math tasks: examples
Here, we’ve included some solved trapezoid practice problems so you can improve your learning.
Solved math task 1
What is the perimeter of this trapezoid?
Answer:
| 84cm |
Perimeter = a + b + c + d
Perimeter = 15cm + 35cm + 14cm + 20cm = 84cm
Solved math task 2
What is the area of this trapezoid?
Answer:
| 260cm2. |
Area= ½ of (a+b)h
Area= ½ of (20+32)10
Area= ½ of 5210
Trapezoid worksheets
Brighterly offers a range of math worksheets, including trapezoid problems to solve, to help you put your learning into practice:
- Trapezoid worksheets
- Area of a trapezoid worksheets
- Area and perimeter worksheets
- Identifying shapes worksheets
Trapezoid: Practice math problems
Frequently Asked Questions
Which shape is a trapezoid?
A trapezoid is a quadrilateral shape that has at least one pair of parallel sides. This is the main trapezoid definition in geometry. It doesn’t matter if the sides are equal or the angles are different, as long as there’s at least one parallel pair.
Do all trapezoids have 4 sides?
Yes, all trapezoids have 4 sides. One pair of these sides runs parallel to each other, which makes it a trapezoid. A trapezoid is made up of four sides plus one parallel pair.
What is the difference between trapezium and trapezoid?
Your location determines the difference. Trapezoids have one pair of parallel sides in the U.S., whereas trapeziums do not. In the U.K., the names are swapped. Different shapes, different labels, which can be confusing unless the region is clarified.
Troubles with Geometry?
- Does your child struggle with understanding of geometry?
- Try learning with an online tutor.
Choose kid's grade
Is your child having difficulties with mastering geometry concepts? An online tutor could provide the necessary help.
Apply now
