Triangle Calculator
Enter all three side lengths of a triangle to calculate its angles, area and perimeter.
How It Works
Angles are found using the law of cosines, and area is found using Heron's formula from the three side lengths.
Example
A 3-4-5 triangle has angles of about 36.87°, 53.13° and 90°, with an area of 6.
Frequently Asked Questions
- What if my side lengths can't form a triangle?
- The calculator checks the triangle inequality (each side must be shorter than the sum of the other two) and shows an error if it's violated.
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