Right Triangle Calculator
Solve a right triangle from any two values: the missing sides, angles, area and perimeter.
About the Right Triangle Calculator
In a right triangle the 90° angle is C, opposite the hypotenuse c. Any two other values, two sides, or a side and an acute angle, determine everything else using Pythagoras and the basic trig ratios.
The formula
sin A = a/c, cos A = b/c, tan A = a/b
- SOH-CAH-TOA
- sine = opposite/hypotenuse, cosine = adjacent/hypotenuse, tangent = opposite/adjacent
Worked example
Leg a = 6, angle A = 30°
- c = 6 ÷ sin 30° = 12
- b = √(144 − 36) ≈ 10.392
Questions people ask
Which side is the hypotenuse?
The longest side, opposite the right angle.
How do I find the height of a ladder?
Ladder length is c, the angle with the ground is B: height = c × sin B.