The Compendium Geometry is an eBook providing facts, formulas and explanations about geometry. 
Home Analytic Geometry Triangle Area of a Triangle  
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Area of a TriangleThe area A of a triangle can be calculated in various ways. The most common one is using a side and its associated the altitude:
Replacing the altitudes in the formulas above by proper sine terms leads to the following equations:
If only one side is known, but all angles are known, then the following formulas can be used:
Further, the area can be calculated from the radius of the incircle, R_{I}, or the circumcircle R_{C} if either all angles or the lengths of all sides are known:
Finally, Heron's formula allows to calculate the area if only the sides are known:


Home Analytic Geometry Triangle Area of a Triangle 