Solve all sides, angles, area, and perimeter of any triangle. Supports SSS, SAS, ASA, and right triangle configurations with trigonometric laws.
Enter all three sides (SSS) to solve the triangle.
Solving triangles involves calculating the missing sides, angles, area, and perimeter from a set of known values. Our free online Triangle Calculator uses trigonometric laws to solve any triangle, supporting side-side-side (SSS), side-angle-side (SAS), angle-side-angle (ASA), and angle-angle-side (AAS) inputs.
The calculator applies standard formulas: the Pythagorean theorem for right triangles, the Law of Cosines (a^2 = b^2 + c^2 - 2bc cos(A)) and the Law of Sines (sin(A)/a = sin(B)/b = sin(C)/c) for oblique triangles. Heron's formula is used to calculate area from three known sides.
Heron's formula calculates the area of a triangle from its three side lengths (a, b, c): Area = sqrt(s(s-a)(s-b)(s-c)), where s is the semi-perimeter: s = (a + b + c) / 2.
The Law of Sines states that the ratio of the length of a side to the sine of its opposite angle is constant for all three sides of a triangle: a/sin(A) = b/sin(B) = c/sin(C).
No, you cannot solve a triangle if only the three angles are known (AAA), because there are infinitely many similar triangles with the same angles but different side lengths. You must know at least one side length.
A right triangle is a triangle in which one of the interior angles is exactly 90 degrees. You can apply the Pythagorean theorem (a^2 + b^2 = c^2) to find missing sides.