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Right Triangle Trigonometry Calculator.

Calculate all six trigonometric ratios from two legs.

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Results update as you type.

Results update automatically as you type.

Use Cases

Solve Right Triangle Problems

Quickly find the trigonometric ratios and angles for a right triangle when you know the lengths of the opposite and adjacent sides. Useful for homework, engineering, or construction.

Example: If opposite = 3 and adjacent = 4, the calculator gives tan(θ) = 0.75 and θ ≈ 36.87°.

Verify Trigonometric Calculations

Check your manual calculations for sine, cosine, and tangent of an angle in a right triangle. Enter your known leg lengths to confirm your results.

Example: For opposite = 5 and adjacent = 12, the calculator shows sin(θ) ≈ 0.3846, cos(θ) ≈ 0.9231, tan(θ) ≈ 0.4167.

Frequently Asked Questions

What does this calculator do?
This calculator uses the lengths of the opposite and adjacent legs of a right triangle to compute the trigonometric ratios (sine, cosine, tangent) and the angle measures. It provides instant results based on the input values.
What inputs are required?
You need to enter the lengths of the opposite leg and the adjacent leg of the right triangle. Both values should be in the same unit (e.g., inches, meters). The calculator then computes the trigonometric functions and the angle.
Can I use this for any right triangle?
Yes, as long as you have the lengths of the two legs (opposite and adjacent) relative to the angle of interest. The calculator assumes a right triangle and uses standard trigonometric definitions.

Tips & Common Mistakes

Tips

  • Ensure both leg lengths are in the same unit before entering them to get accurate results.
  • Remember that the opposite and adjacent legs are relative to the angle you are analyzing. Swap them if you need the other acute angle.
  • Use the tangent ratio (opposite/adjacent) to find the angle when you have the two legs, as it directly relates them.
  • Double-check your inputs for typos, as small errors can significantly affect the computed angle.

Common Mistakes to Avoid

  • Entering the hypotenuse instead of one of the legs. This calculator only uses the opposite and adjacent legs.
  • Mixing units (e.g., entering one leg in inches and the other in centimeters) without converting, leading to incorrect ratios.
  • Assuming the calculator provides the hypotenuse; it only computes trigonometric functions and angles based on the given legs.

Last updated: August 13, 2026