Triangle Calculator

How the calculation works

Choose what you know. The calculator uses the law of cosines and law of sines to find the missing sides and angles, then shows the area, perimeter, inradius and circumradius. For the SSA case, it shows both solutions when two triangles are possible.

Formula used

Law of cosines: c² = a² + b² − 2ab cos C; Law of sines: a ÷ sin A = b ÷ sin B; Area = √(s(s−a)(s−b)(s−c))

Example

Sides 3, 4 and 5 form a right triangle with angles 36.87°, 53.13° and 90°, and an area of 6.