Herons Formula Calculator
From Three Side Lengths
Find Third Side from Area and Two Sides
Formula
A = sqrt(s(s-a)(s-b)(s-c)) where s = (a+b+c)/2
Frequently Asked Questions
What is Herons formula?
Herons formula calculates the area of a triangle when you know all three side lengths: Area = sqrt(s(s-a)(s-b)(s-c)), where s = (a+b+c)/2 is the semi-perimeter.
When should you use Herons formula?
Use it when you know all three sides but not the height or angles. It is especially useful when finding the height would be difficult.
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