Right triangle calculator: sides, angles and area
The right angle is at C. Legs a and b form the right angle, c is the hypotenuse, angle A faces side a.
Result
5Hypotenuse c
- Leg a
- 3
- Leg b
- 4
- Angle A
- 36.8699°
- Angle B
- 53.1301°
- Area
- 6
- Perimeter
- 12
- Height from the right angle
- 2.4
Inputs
- You know
- Both legs a and b
- Leg a
- 3
- Leg b
- 4
- Angle unit
- Degrees
How it is calculated
c² = a² + b² (Pythagoras).
Result
Hypotenuse c
- Leg a
- 3
- Leg b
- 4
- Angle A
- 36.8699°
How it is calculated
- c² = a² + b² (Pythagoras).
- sin A = a ÷ c, cos A = b ÷ c, tan A = a ÷ b; B = 90° − A.
- Area = a × b ÷ 2; height to the hypotenuse = a × b ÷ c.
Example
a = 3 and b = 4: c = 5, A ≈ 36.8699°, B ≈ 53.1301°, area 6, perimeter 12, height 2.4.
Good to know
- The given angle must be strictly between 0 and 90°: otherwise it is not a right triangle.
- The hypotenuse must be longer than the other side.
- Check the angle unit: 30 radians is not 30°.
Frequently asked questions
What is this tool used for?
The right angle is at C. Legs a and b form the right angle, c is the hypotenuse, angle A faces side a.
How is the result calculated?
c² = a² + b² (Pythagoras).
What should I check before using the result?
The given angle must be strictly between 0 and 90°: otherwise it is not a right triangle.