Right Angle Triangle Calculator
This calculator solves a right-angle triangle, known outside New Zealand simply as a right triangle, working out the missing side length, both non-right angles, and the total area from whatever two measurements you already know. A right-angle triangle has one fixed 90-degree corner, so knowing just two sides is enough to find everything else using the Pythagorean theorem and basic trigonometry. That makes it handy for real jobs such as checking a deck or wall frame is square, working out a rafter length for a roof pitch, sizing a ramp or stairs, or solving a maths or trade assignment. To use it, enter any two of the three side lengths, height (a), base (b) or hypotenuse (c), and leave the third as is. Click Calculate and the missing side fills in, along with angle A, angle B in degrees, and the triangle's area. Enter the two shorter sides to find the hypotenuse, or the hypotenuse plus one other side to find the remaining side. The diagram above the fields shows which side is which, so there is no guesswork over measurements. Reset clears every field back to zero for a fresh calculation. Because the maths is exact geometry rather than an estimate, the results are accurate for any right-angle triangle, though it is still worth double-checking your own measurements before cutting material or relying on the figures for a physical build.
