How to calculate the Area of a Triangle

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This is a simple math tutorial aimed at middle school students, explaining how to calculate the area of a triangle (and the reasoning behind the method).

How to calculate the area of a triangle

The previous tutorials described the most commonly used method for calculating the area of a four-sided shape, be it a square, rectangle or parallelogram: by multiplying its width by its height.

A triangle is not that much different. As you can see below, two triangles that are of mirror image, can combine to create a four sided shape.

You can see in the above video tutorial how this works with any type of triangle. This means that the area of a triangle is exactly half that of a four-sided shape with the same height and width.

This is demonstrated in the below example.


If you'd like to practice your area calculations, there is a free complimentary worksheet with four exercises for you to work through in your own time. There are also worked-out solutions for you to compare your answers against. You can check out the worksheet below, or download it from here: