Worksheets · Algebra 2

Coterminal and reference angles worksheet for Algebra 2

Coterminal angles land in the same place, so add or subtract whole turns. A reference angle is the acute angle to the x-axis, which is what makes every trig value in any quadrant computable from the first one.

Also taught in Precalculus, at its own level and with its own examples.

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Pick more than one for a sheet that mixes them.

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

Sigma Prep · sigmaprep.io/worksheets

Name

Coterminal and Reference Angles

Date Period

Answer each question.

  1. Find a coterminal angle

    Find the coterminal angle in [0∘,360∘): −135∘
  2. Find the coterminal angle in [0∘,360∘): 870∘
  3. Find the coterminal angle in [0∘,360∘): −240∘
  4. Find the coterminal angle in [0∘,360∘): 1035∘
  5. Find the coterminal angle in [0∘,360∘): −150∘
  1. Find the reference angle

    An angle of 340∘ is in standard position. Find its reference angle.
  2. Find the reference angle of 60∘.
  3. What is the reference angle of 135∘?
  4. What is the reference angle of 250∘?
  5. Find the reference angle of 35∘.
  1. Find a coterminal angle in radians

    Find the coterminal angle in [0,2π): 10π3
  2. Find the coterminal angle in [0,2π): 8π3
  3. Find the coterminal angle in [0,2π): 7π2
  4. Find the coterminal angle in [0,2π): 9π4
  5. Find the coterminal angle in [0,2π): 11π3
  1. Find the reference angle in radians

    Find the reference angle of 4π3.
  2. What is the reference angle for an angle of −7π6 in standard position?
  3. θ=−π12. Find the reference angle of θ.
  4. θ=7π12. Find the reference angle of θ.
  5. What is the reference angle for an angle of 7π4 in standard position?

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

Sigma Prep · sigmaprep.io/worksheets

Name

Coterminal and Reference AnglesAnswer keyVersion 1

Date Period

Answer each question.

  1. Find a coterminal angle

    Find the coterminal angle in [0∘,360∘): −135∘225∘
  2. Find the coterminal angle in [0∘,360∘): 870∘150∘
  3. Find the coterminal angle in [0∘,360∘): −240∘120∘
  4. Find the coterminal angle in [0∘,360∘): 1035∘315∘
  5. Find the coterminal angle in [0∘,360∘): −150∘210∘
  1. Find the reference angle

    An angle of 340∘ is in standard position. Find its reference angle.20∘
  2. Find the reference angle of 60∘.60∘
  3. What is the reference angle of 135∘?45∘
  4. What is the reference angle of 250∘?70∘
  5. Find the reference angle of 35∘.35∘
  1. Find a coterminal angle in radians

    Find the coterminal angle in [0,2π): 10π34π3
  2. Find the coterminal angle in [0,2π): 8π32π3
  3. Find the coterminal angle in [0,2π): 7π23π2
  4. Find the coterminal angle in [0,2π): 9π4π4
  5. Find the coterminal angle in [0,2π): 11π35π3
  1. Find the reference angle in radians

    Find the reference angle of 4π3.π3
  2. What is the reference angle for an angle of −7π6 in standard position?π6
  3. θ=−π12. Find the reference angle of θ.π12
  4. θ=7π12. Find the reference angle of θ.5π12
  5. What is the reference angle for an angle of 7π4 in standard position?π4

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

How to do these

Find the reference angle: 210∘

  1. 210 is in the third quadrant.
  2. The reference angle is the distance to the x-axis.
  3. 210 minus 180.

The answer is 30∘.

Where students go wrong

Measuring the reference angle from the y-axis, or subtracting from 360 in the wrong quadrant. It is always to the nearest part of the x-axis, so the answer is always between 0 and 90.

Also called positive coterminal angle or finding reference angles.

What you can put on this worksheet

Coterminal angles
Find the coterminal angle in [0∘,360∘): 930∘ → 210∘
Reference angles
What is the reference angle of 235∘? → 55∘
Which quadrant an angle ends in
In which quadrant, or on which axis, does 187∘ end? → Quadrant III
Sketch an angle in standard position
Sketch 190∘ in standard position. Where does its terminal side lie? — axes for sketching an angle → Quadrant III
Coterminal angles in radians
Find the coterminal angle in [0,2π): 11π3 → 5π3
Reference angles in radians
Find the reference angle of 4π3. → π3
Negative and radian angles, read from a drawing, coterminal or not
Find one positive and one negative coterminal angle:
13π12
→ 37π12,−11π12
Angles with a given reference angle
List four angles between 0∘ and 720∘, one in each quadrant, with reference angle 20∘ → For example:
20∘, 340∘, 520∘, 560∘
The whole angle from a drawing, in radians
Find the measure of the angle, in radians. — an angle in standard position, labeled x, y, π/4 → 5π4

Questions about these worksheets

Yes. Every coterminal and reference angles 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.

Algebra 2 is usually taken around 10th or 11th 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 coterminal and reference angles 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 9: coterminal angles, reference angles, which quadrant an angle ends in, sketch an angle in standard position, coterminal angles in radians, reference angles in radians, negative and radian angles, read from a drawing, coterminal or not, angles with a given reference angle and the whole angle from a drawing, in radians. Tick as many as you want and set how many of each, or let it spread them evenly.

Measuring the reference angle from the y-axis, or subtracting from 360 in the wrong quadrant. It is always to the nearest part of the x-axis, so the answer is always between 0 and 90.