Heron's Formula for Area of a Triangle - Geometry Calculator


Online calculator to calculate the area of a triangle using Heron's formula. This formula is used when all three sides of a triangle are given. let a, b and c be the lengths of the three sides of the triangle. The calculator first check that the 3 given sides corresponds to that of a triangle by checking the following triangle inequalities:

a + b < c , b + c < a and c + a < b

Then the area of this triangle is calculated using Heron's formula given by:

A = √ s (s - a) (s - b) (s - c)


where s in the above formula is given by s = (1 / 2)(a + b + c).

How to use the calculator

Enter the three sides a, b and c, of the triangle, as positive real numbers and press "enter". The output is the area and the triangle. For the three sides a, b and c to define a triangle, the sum of the lengths of any two sides must be larger than the length of the third side. Note that if the three sides do not define a triangle 'No Triangle Exists' is displayed.

a =
b =
c =
area =

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