Worksheets · Precalculus

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.

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Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep

Sigma Prep · sigmaprep.io/worksheets

Name

Right Triangle Trigonometry

Date Period

Answer each question.

  1. Find the sine

    A right triangle has legs 180 and 33 and hypotenuse 183. Find sin⁡A, where A is opposite the side of length 33.
  2. In right triangle ABC, ∠C=90∘, BC=30, AC=16 and AB=34. Find sin⁡B.
  3. In right triangle ABC, ∠C=90∘, BC=360, AC=66 and AB=366. Find sin⁡A.
  4. A right triangle has legs 60 and 63 and hypotenuse 87. Find sin⁡A, where A is opposite the side of length 60.
  1. Find the cosine

    In right triangle ABC, ∠C=90∘, BC=33, AC=56 and AB=65. Find cos⁡A.
  2. A right triangle has legs 385 and 336 and hypotenuse 511. Find cos⁡A, where A is opposite the side of length 336.
  3. A right triangle has legs 105 and 36 and hypotenuse 111. Find cos⁡A, where A is opposite the side of length 105.
  4. In right triangle ABC, ∠C=90∘, BC=140, AC=48 and AB=148. Find cos⁡B.
  1. Find the tangent

    A right triangle has legs 220 and 192 and hypotenuse 292. Find tan⁡A, where A is opposite the side of length 220.
  2. In right triangle ABC, ∠C=90∘, BC=300, AC=55 and AB=305. Find tan⁡B.
  3. In right triangle ABC, ∠C=90∘, BC=168, AC=160 and AB=232. Find tan⁡A.
  1. Find a side using a special angle

    In right triangle PQR, the right angle is at R, ∠P=30∘ and PR=36. Find PQ. Give an exact answer.
  2. A right triangle has a 60∘ angle, and the leg adjacent to it is 6. Find the other leg. Give an exact answer.
  3. A guy wire from the top of a pole meets the ground at 45∘. The pole is 12 ft tall. Find the length of the wire, exactly.
  1. Find trig values and angles

    cos⁡θ=0.1. Find θ to the nearest tenth of a degree.
  2. Find cos⁡20∘ to four decimal places.
  3. sin⁡θ=0.421. Find θ to the nearest tenth of a degree.
  1. Find the missing angle

    Find m∠E to the nearest tenth of a degree.185153104DEF
  2. Find θ to the nearest tenth of a degree.734855θ
  3. Use the three sides to find θ, to the nearest tenth of a degree.12544117θ

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.

  1. Find the sine

    A right triangle has legs 180 and 33 and hypotenuse 183. Find sin⁡A, where A is opposite the side of length 33.1161
  2. In right triangle ABC, ∠C=90∘, BC=30, AC=16 and AB=34. Find sin⁡B.817
  3. In right triangle ABC, ∠C=90∘, BC=360, AC=66 and AB=366. Find sin⁡A.6061
  4. A right triangle has legs 60 and 63 and hypotenuse 87. Find sin⁡A, where A is opposite the side of length 60.2029
  1. Find the cosine

    In right triangle ABC, ∠C=90∘, BC=33, AC=56 and AB=65. Find cos⁡A.5665
  2. A right triangle has legs 385 and 336 and hypotenuse 511. Find cos⁡A, where A is opposite the side of length 336.5573
  3. A right triangle has legs 105 and 36 and hypotenuse 111. Find cos⁡A, where A is opposite the side of length 105.1237
  4. In right triangle ABC, ∠C=90∘, BC=140, AC=48 and AB=148. Find cos⁡B.3537
  1. Find the tangent

    A right triangle has legs 220 and 192 and hypotenuse 292. Find tan⁡A, where A is opposite the side of length 220.5548
  2. In right triangle ABC, ∠C=90∘, BC=300, AC=55 and AB=305. Find tan⁡B.1160
  3. In right triangle ABC, ∠C=90∘, BC=168, AC=160 and AB=232. Find tan⁡A.2120
  1. Find a side using a special angle

    In right triangle PQR, the right angle is at R, ∠P=30∘ and PR=36. Find PQ. Give an exact answer.243
  2. A right triangle has a 60∘ angle, and the leg adjacent to it is 6. Find the other leg. Give an exact answer.63
  3. A guy wire from the top of a pole meets the ground at 45∘. The pole is 12 ft tall. Find the length of the wire, exactly.122
  1. Find trig values and angles

    cos⁡θ=0.1. Find θ to the nearest tenth of a degree.84.3∘
  2. Find cos⁡20∘ to four decimal places.0.9397
  3. sin⁡θ=0.421. Find θ to the nearest tenth of a degree.24.9∘
  1. Find the missing angle

    Find m∠E to the nearest tenth of a degree.185153104DEF34.2∘
  2. Find θ to the nearest tenth of a degree.734855θ48.9∘
  3. Use the three sides to find θ, to the nearest tenth of a degree.12544117θ69.4∘

Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep

How to do these

A right triangle has legs 20 and 21 and hypotenuse 29. Find tan⁡A, where A is opposite the side of length 20

  1. Tangent is opposite over adjacent.
  2. The side opposite A is 20 and the leg next to it is 21.

The answer is 2021.

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 ABC, ∠C=90∘, BC=45, AC=24 and AB=51. Find sin⁡A. → 1517
Cosine from the three sides
In right triangle ABC, ∠C=90∘, BC=45, AC=24 and AB=51. Find cos⁡A. → 817
Tangent from the three sides
In right triangle ABC, ∠C=90∘, BC=45, AC=24 and AB=51. Find tan⁡A. → 158
A missing side from a special angle
A right triangle has hypotenuse 12 and an angle of 45∘. Find the side adjacent to it. Give an exact answer. → 62
Cosecant, secant and cotangent from the sides
A right triangle has legs 45 and 24 and hypotenuse 51. Find csc⁡A, where A is opposite the side of length 45 → 1715
A missing side, any angle, rounded
Find the length x to the nearest tenth. — a right triangle with a 47° angle, legs 13 and x, hypotenuse unknown → 13.9
An angle from two sides, with inverse trig
Find θ. Round to the nearest degree. — a right triangle with a θ angle, legs 20 and 13, hypotenuse unknown → 33∘
Ratios and angles on a calculator
Find cos⁡50∘ to four decimal places. → 0.6428
All three sides given: find the angle
Use the three sides to find θ, to the nearest tenth of a degree. — a right triangle, labeled 34, 30, 16, θ → 28.1∘
A ratio read off a drawing, as a fraction
Find cos⁡A. — a right triangle, labeled 34, 30, 16, A, B, C → 817
A ratio read off a drawing, to four decimal places
Find cos⁡S to four decimal places. — a right triangle, labeled 17, 15, 8, S, T, U → 0.4706
One ratio given, find another
Angle A is acute and tan⁡A=409. Find sin⁡A → 4041
Sides with roots, csc sec cot values, from one ratio to another
Find the value to four decimal places: cot⁡ ⁣(11∘) → 5.1446
Calculator values in radians
In radian mode, find cos⁡(3π/10), to four decimal places. → 0.5878

Questions about these worksheets

Yes. Every right triangle trigonometry sheet is free to print and free to download as a PDF. There is no account to make, no email to hand over and no limit on how many you take.

Yes. The answer key prints on a second page, and you can choose whether it shows each question beside its answer or just the answers in a list.

Yes. Print straight from the page, or download the PDF and print that. The sheet is laid out for paper rather than squeezed off a screen, so there is room to work under each question, and the answer key comes out on its own page.

Precalculus is usually taken around 11th or 12th grade, though schools vary and plenty of students meet it earlier or later. Pick the difficulty rather than the grade: the easy level suits a first lesson on it, the hard level suits review before a test.

Yes, as many as you like. The questions are built fresh each time rather than picked from a fixed set of files, so pressing Generate gives a new sheet. That is what you want for a second class, a retake, or two students sitting next to each other.

That is the closest comparison, and Kuta Software is good software. It is also paid software you install on a computer. These worksheets run in a browser tab for free, with no account and nothing to install. Like Kuta, the right triangle trigonometry questions are generated when you ask for them rather than pulled from a fixed set of files, so two classes never get the same sheet, and the answer key comes with it.

Yes. There are two levels, and you can tick more than one for a sheet that mixes them, in which case the questions come out easiest first. The harder levels are not just larger numbers: they ask for something the easy ones do not.

You pick from 14: sine from the three sides, cosine from the three sides, tangent from the three sides, a missing side from a special angle, cosecant, secant and cotangent from the sides, a missing side, any angle, rounded, an angle from two sides, with inverse trig, ratios and angles on a calculator, all three sides given: find the angle, a ratio read off a drawing, as a fraction, a ratio read off a drawing, to four decimal places, one ratio given, find another, sides with roots, csc sec cot values, from one ratio to another and calculator values in radians. Tick as many as you want and set how many of each, or let it spread them evenly.

Using the hypotenuse as the adjacent side. The hypotenuse is never the adjacent one: adjacent means the leg next to the angle, and the hypotenuse has its own name for a reason.