The document presents information about Heron's formula for calculating the area of a triangle when the lengths of all three sides are known. It defines Heron's formula as the square root of s(s-a)(s-b)(s-c)/2, where s is the semi-perimeter or half the perimeter, and a, b, c are the lengths of the three sides. It also provides some biographical details about Heron, the Greek mathematician who developed the formula, and demonstrates solving an example using the formula.