How to use the Right Triangle Calculator
The right triangle calculator gives the missing side, area, perimeter and angles.
Open the Right Triangle Calculator →
What you need to enter
- Solve for
- Side a
- Side b
- Hypotenuse c
The formula
c = √(a² + b²). Angle A = arctan(a ÷ b). Area = ½ab.
Worked example
Using the default values in the calculator:
- Solve for: Hypotenuse c
- Side a: 3
- Side b: 4
- Hypotenuse c: 5
| Hypotenuse c | 5 |
| Area | 6 |
| Perimeter | 12 |
| Angle A | 36.8699° |
| Angle B | 53.1301° |
Tips for better results
- Angles add to 90° besides the right angle.
- Use consistent units.
Common mistakes to avoid
- Mixing up legs and hypotenuse.
- Rounding too early.