Area of Triangle Using Sine Formula

Area of a Triangle Formula

Online calculator to calculate the area of a triangle given its two sides and the included angle.

Triangle diagram showing sides a, b, c and angles A, B, C

The above triangle has angles \( A, B \) and \( C \) and the respective opposite sides \( a, b \) and \( c \).
The area of a triangle given two of its sides and the angle they make is given by one of these 3 formulas:

\[ Area = \dfrac{1}{2} \cdot b \cdot c \cdot \sin(A) = \dfrac{1}{2} \cdot c \cdot a \cdot \sin(B) = \dfrac{1}{2} \cdot a \cdot b \cdot \sin(C) \]

How to use the calculator

Here we assume that we are given any two sides \( x \) and \( y \) and the angle between them \( \theta \). Enter sides \( x \) and \( y \) and angle \( \theta \) in degrees as positive real numbers, choose how many decimal places to display, and press "Calculate Area". The output is the area of the triangle.

Triangle Area Calculator

Enter two sides and the included angle (in degrees)

-- square units

More References and Links

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