This calculator calculates the area of a triangle given two sides and the included angle (in radians).
Learn how to use the calculator to calculate the area of a triangle.
This calculator uses the formula for the area of a triangle when two sides and the included angle are known:
Area = 0.5 × side1 × side2 × sin(angle)
This formula works because the area of a triangle can be thought of as half the product of the base and height. When you know two sides and the included angle, you can determine the height using trigonometry, and then use the standard area formula.
Suppose you have a triangle with sides of 5 km and 7 km, and the angle between them is 1.2 radians. The area would be:
Area = 0.5 × 5 × 7 × sin(1.2) ≈ 14.9494 km²