# How To Find Area Of A Trapezoid

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## How To Find Area Of A Trapezoid

Rectangle, square triangle etc are familiar to us. But what about a trapezoid? Here is a video on how to workout the area of a trapezium.

Let us workout the area of the following trapezoid. Important things to notice on a trapezium are the different sidelines that we have. This one here is three centimeters and this one here, let us say, is five centimeters.

We also need to know the height from the lowest point of the trapezium to the highest point. Let us say that for ours is two centimeters. What we now do to find the area is use the following formulae.

We use the formula H*(a+b)/2. Now this looks really complicated. But all it's saying is, let us take one side length 'a', for this that might be three, add it to the other side length, that is five for our example, and divide that by two.

So, 'a' and 'b' are just the sidelengths on your trapezium. The 'h' corresponds to the height, just as it does in the area of a triangle. So let us take it step by step.

The first step, let us substitute our numbers in. We have 'h' which is equal to two, 'a' and 'b' are three plus five. Then we divide this by two, and let us simplyfy this on the next line.

Two, eight divided by two. Because eight comes from three plus five.We now simplify this fraction to give us four because eight divided by two is four, and we have the following.

Two bracket four. Which we know, expands to give us eight. Butremember your units are centimeter square, because you are dealing with area.

The way to think about this and the way to remember the formula is that here, we are basically working out the average side length. We have taken both side lengths, added them together and dividing them by two. Once we have the average sidelength, we multiply it by the height.

And that is how you can remember the formula. Just to recap, we take the formula, we substitute our values in, we simplify this down and that gives us our answer. And remember, your units are cenimeter square.

And this is how to workout the area of the trapezoid or trapezium. .