Right Triangle Calculator
Solve a right triangle from any two values - legs, hypotenuse, or an acute angle - with steps for sides, angles, and area.
Solve a right triangle
Right angle is fixed at C = 90°. Enter any two values, including at least one side.
Answer
Right triangle solved
- Right angle at C = 90°.
- Sides: a = 3, b = 4, c = 5
- Angles: A = 36.86989765°, B = 53.13010235°, C = 90°
- Perimeter = 12
- Area = 6
How to use the right triangle calculator
With the right angle fixed at C = 90°, enter any two values (including at least one side) to find the remaining sides, both acute angles, the perimeter, and the area.
- Keep the right angle at C = 90°.
- Enter any two values with at least one side.
- Use the Pythagorean theorem for a missing side, or trig ratios when an angle is known.
- Read the full set of sides, angles, perimeter, and area.
Formula or method
a^2 + b^2 = c^2; tan A = a / b; area = (a * b) / 2.
Worked examples
Two legs
Problem: a = 3, b = 4
Solution: c = sqrt(3^2 + 4^2) = 5; A ≈ 36.87°, B ≈ 53.13°; area = 6.
Leg and angle
Problem: a = 6, A = 30
Solution: c = a / sin 30 = 12, b = c * sin 60 ≈ 10.39.