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Right-angle triangle calculator

Enter any two values, including at least one side, and leave the rest blank. Handy for hole positions, angled cuts and checking a set-up.

ABbac

Any length unit works; answers use the same unit.

How it works, guides and notes

How it works

A right-angled triangle is fixed once you know two things about it, as long as one is a length. The three ratios do all the work: sin A = a ÷ c, cos A = b ÷ c and tan A = a ÷ b. The two acute angles always add to 90°.

Worked example: a hole 30 mm along a line at 30° from a datum: c = 30 ÷ sin 30° = 60 mm, b = 30 ÷ tan 30° = 51.962 mm.

For holes on a circle, use the PCD calculator; for angles from a height, the sine bar calculator.

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