Triangle Area Calculator (Trigonometry)
Calculate triangle area using two sides and the included angle
About this calculator
This Triangle Area Calculator uses trigonometry to find the area of any triangle when you know two sides and the included angle between them. It applies the formula Area = (1/2) × a × b × sin(C), where a and b are the two known sides and C is the angle between them. This method is particularly useful for solving real-world problems in construction, engineering, surveying, and geometry homework when you don't have the triangle's height measurement readily available.
How to use
Enter the lengths of two sides of your triangle in the designated input fields. Then input the measure of the angle between those two sides (the included angle) in degrees. Click calculate to instantly get the triangle's area using the trigonometric formula.
Frequently asked questions
What is the included angle in a triangle?
The included angle is the angle formed between two known sides of a triangle, located at the vertex where those two sides meet.
Can I use this calculator with obtuse angles?
Yes, this calculator works with any angle measure from 0° to 180°, including acute, right, and obtuse angles in triangles.
What units can I use for the side lengths?
You can use any unit of measurement (inches, feet, meters, etc.) as long as both sides use the same unit consistently.