Right Triangle Calculator
The right triangle calculator helps you find the sides and area of a right triangle.
Solved for hypotenuse c5
Legs3 and 4
Hypotenuse5
Area6
Perimeter12
Angles36.8699°, 53.1301°, 90°
Is it a Pythagorean triple?Yesall three sides whole numbers
Working
| a² | 9 |
| b² | 16 |
| a² + b² | 25 |
| c² | 25 |
| c = √(a² + b²) | 5 |
The formula
a² + b² = c²
What always holds
- The three angles add to 180°, without exception.
- Any two sides must add to more than the third — the triangle inequality. Sides of 4, 5 and 12 cannot close.
- The longest side always faces the largest angle.
Area = ½ × base × heightfor any triangle, with the height measured perpendicular to that base.
Which formula to reach for
With three sides, use Heron’s formula. With a base and its height, use ½bh. With two sides and the angle between them, use ½ab·sin C. With a right angle, the two legs are already base and height, so the area is just half their product.