Right triangle trigonometry worksheet for Precalculus
In Precalculus right triangle ratios are the starting point for the unit circle: sine, cosine and tangent from the three sides, exact sides from special angles, and angles found with an inverse function and rounded to the tenth of a degree.
Also taught in Algebra 2, Geometry and Algebra 1, each at its own level and with its own examples.
Not quite the one you need? Same words, different skill:
- Special Right Triangles (Geometry). 45-45-90 and 30-60-90.
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Pick more than one for a sheet that mixes them.
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Sigma Prep · sigmaprep.io/worksheets Name Right Triangle Trigonometry Date Period Answer each question.
Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep |
Sigma Prep · sigmaprep.io/worksheets Name Right Triangle TrigonometryAnswer keyVersion 2 Date Period Answer each question.
Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep |
How to do these
A right triangle has legs and and hypotenuse . Find , where is opposite the side of length
- Tangent is opposite over adjacent.
- The side opposite A is 20 and the leg next to it is 21.
The answer is .
Where students go wrong
Using the hypotenuse in tangent. Tangent is opposite over adjacent, the two legs; only sine and cosine have the hypotenuse on the bottom.
Also called SOHCAHTOA, trig ratios or finding missing sides.
What you can put on this worksheet
- Sine from the three sides
- In right triangle , , , and . Find . →
- Cosine from the three sides
- In right triangle , , , and . Find . →
- Tangent from the three sides
- In right triangle , , , and . Find . →
- A missing side from a special angle
- A right triangle has hypotenuse and an angle of . Find the side it. Give an exact answer. →
- Cosecant, secant and cotangent from the sides
- A right triangle has legs and and hypotenuse . Find , where is opposite the side of length →
- A missing side, any angle, rounded
- Find the length to the nearest tenth. — a right triangle with a 47° angle, legs 13 and x, hypotenuse unknown →
- An angle from two sides, with inverse trig
- Find . Round to the nearest degree. — a right triangle with a θ angle, legs 20 and 13, hypotenuse unknown →
- Ratios and angles on a calculator
- Find to four decimal places. →
- All three sides given: find the angle
- Use the three sides to find , to the nearest tenth of a degree. — a right triangle, labeled 34, 30, 16, θ →
- A ratio read off a drawing, as a fraction
- Find . — a right triangle, labeled 34, 30, 16, A, B, C →
- A ratio read off a drawing, to four decimal places
- Find to four decimal places. — a right triangle, labeled 17, 15, 8, S, T, U →
- One ratio given, find another
- Angle is acute and . Find →
- Sides with roots, csc sec cot values, from one ratio to another
- Find the value to four decimal places: →
- Calculator values in radians
- In radian mode, find , to four decimal places. →