Area of a scalene triangle

The area of a scalene triangle can be calculated using Heron’s formula if all its sides (a, b and c) are known.

It could also be calculated if a side (b) is known and the height (h) associated with that side.

Finally, the area of a scalene triangle can also be calculated by trigonometric procedures, provided that three elements of the triangle are known, at least one of which is a side.

Exercise

Find the area of the scalene triangle given its three sides: a=2 cm, b=4 cm and c=3 cm.

What is its area?

We can calculate the area using Heron’s formula. First, we have to determine the semiperimeter s:

Now, we can apply the Heron’s formula:

So the area is 2.9 cm².

Table of Triangle Area Formulas

You can see the table of triangle area formulas . Depending on the type of triangle you may need one element (scalene triangle), two (base and height) or three (as long as they are not the three angles).