Triangle Calculator
Enter the three side lengths to get the triangle's area, perimeter and all three angles, and to see whether it is right, acute or obtuse.
Type a number and the answer appears straight away.
Your answer
Area6
- Perimeter
- 12
- Angle A (opposite side a)
- 36.87°
- Angle B (opposite side b)
- 53.13°
- Angle C (opposite side c)
- 90°
- Type
- Scalene, right
The math behind it: Triangle Calculator
area = √(s(s - a)(s - b)(s - c)) where s = (a + b + c) / 2
The area uses Heron's formula, and the angles come from the law of cosines. Three lengths only make a triangle if each one is shorter than the other two added together.
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