Area of a Triangle from Sides
You can calculate the area of a triangle if you know the lengths of all three sides, using a formula that has been know for nearly 2000 years.
It is called "Heron's Formula" after Hero of Alexandria (see below) Just use this two step process:

Step 1: Calculate "s" (half of the triangles perimeter) using:

Step 2: Then calculate the Area using:

2 4 2