The way you calculate the area of a triangle mainly depends on the kind of triangle and how much information you have about it. In instances where your not given the height and the base you can use this formula.

This formula is only applicable where you are given the measure of the three sides.The semi-perimeter, p can easily be calculated by adding all the sides and dividing by 2.

## Example

If a=4cm b=cm and c=9cm Calculate the area of that triangle.

You can start off by calculating the semi perimeter,p;

Now that we have P, all we need to do is feed the values of a,b,c and p into the formula and we will get the area.

So despite not knowing the base or vertical height of the triangle, we were able to calculate the area using this formula. And found it to be 9.56 cm squared.

This formula was introduced in 1st century B.C. by a great mathematician called Heron.