Trigonometry - Heron's Formula

Heron's formula provides a method to calculate the area of a triangle when you know the lengths of all three sides. To use the formula, first calculate the semi-perimeter of the triangle s, which is half the perimeter of the triangle, or the sum of the sides divided by two. Then, the area A can be found by taking the square root of s multiplied by the product of s subtracted by each side length. The result is expressed in square units, the same as the units used for the side lengths.

This can be particularly useful in surveying, navigation, astronomy, and computer graphics where determining areas of irregular polygons may be needed based on knowledge of the side lengths.