Area of a Triangle (Given 3 Sides) (Heron's Formula)
You can calculate the area of a triangle using THREE sides lengths (and no angles!):
Step 1. Find the "Semiperimeter", which is the perimeter divided by 2.
Step 2. Find the differences between the Semiperimeter and each side (three different differences)
Step 3. Multiply those three differences together AND multiply by the semiperimeter once more.
Step 4. Square root that product.