A trapezoid is a flat shape with four straight sides. Two of the sides run parallel with one another and are opposite to one another.

Trapezoid

The trapezoid doesn’t have to be a small figure, as the lengths of the sides and the angles can vary greatly. While some people think the trapezoid is a term reserved strictly for math books, real-life examples of trapezoid shapes can be found in handbags, bridge truss supports, popcorn tins, and some musical instruments such as the guitar-like dulcimer.

The area of a trapezoid

Students sometimes get confused when it comes to finding the area of a trapezoid, simply because they do not know how to properly label the shape so they can plug the right numbers into the formula. These key facts will help determine the right numbers to use in the formula for finding the area of a trapezoid:

  • The two sides that run parallel to one another are called the bases.
  • The other two sides are referred to as the legs.
  • The distance between the two bases is referred to as the altitude or the height.

Formula for the area of the trapezoid

When finding the area of the trapezoid, there is a simple formula to follow. As long as you place the correct numbers into the formula and do not make simple mistakes in adding, dividing, and multiplying, you will easily be able to come up with your final answer. The formula is as follows:

Area = ½ (a + b) h

The top base line is referred to as “a.”

The bottom base line is referred to as “b.”

The altitude is referred to as “h.”

How to find the area of a trapezoid (EXAMPLE)

Example: Let’s suppose our trapezoid has bases that are 6 meters and 8 meters long and a height of 4 meters so our formula would look like this.

½ (6m + 8m) x 4m = 28 m².

Step 1: First, the two bases will need to be added together. So, we say 5m + 8m = 14m.

Step 2: Divide the number you got from adding the bases by 2. So you will say 14 divided by 2, which equals 7.

Step 3: You will take 7 and multiply it by “h” which is 4.


Answer: The answer to this problem would be 28 m²


When searching for the area of a trapezoid, it is important you do not mix up the numbers and you plug them in their rightful place in the formula so you can find the right area. Mixing up a single number will lead to a completely wrong answer, even if you know the correct formula to follow.

Trapezoids are commonly found in furniture designs, such as tables, and in other objects like signs. There are many reasons a person might need to find the area of an object, such as planning for a building project, painting, and making a cover for a table.

Fun fact about trapezoids

There is often confusion when it comes to the meaning of trapezoids and what the term means in the US and the UK. In the US, the term means a quadrilateral with one pair of parallel sides while in the UK, a trapezoid has no parallel sides.