How to solve a triangle
- Enter any three of the six values: sides a, b, c and the angles A, B, C opposite them, in degrees. At least one must be a side.
- Leave the other three empty.
- Read every side and angle, the area, perimeter, heights and the triangle’s type.
Types of triangle
- By sides: equilateral (all equal), isosceles (two equal), scalene (none equal).
- By angles: acute (all under 90°), right (one exactly 90°), obtuse (one over 90°).
Checks
The angles always add up to 180°, and each side must be shorter than the other two together. If the values you enter break either rule, the calculator says so instead of giving a triangle that can’t exist.