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.
Download this calculator to get the results of the formulas on this page. Choose the initial data and enter it in the upper left box. For results, press ENTER.
Triangle-total.rar or Triangle-total.exe
Note. Courtesy of the author: José María Pareja Marcano. Chemist. Seville, Spain.
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).

AUTHOR: Bernat Requena Serra
YEAR: 2020