Worksheets · Pre-Algebra

Pre-Algebra angle relationships worksheet

Two angles that make a right angle are complementary; two that make a straight line are supplementary. The harder levels give the pair as a ratio instead of a number.

Select your difficulty

Pick more than one for a sheet that mixes them.

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

Sigma Prep · sigmaprep.io/worksheets

Name

Angle Relationships

Date Period

Find each angle.

  1. Find the complementx
  2. Find the supplement172°x
  3. Two supplementary angles are in the ratio 1:4. Find the smaller one
  4. Find the complement63°x
  5. Find the supplement175°x
  6. Two complementary angles are in the ratio 2:7. Find the smaller one
  7. Find the complement37°x
  8. Find the supplement31°x
  9. Two complementary angles are in the ratio 1:2. Find the smaller one
  10. Find the complement67°x
  11. Find the supplement37°x
  12. Two complementary angles are in the ratio 1:5. Find the smaller one
  13. Find the complement69°x
  14. Find the supplement40°x
  15. Two supplementary angles are in the ratio 2:7. Find the smaller one
  16. Find the complement20°x
  17. Find the supplement82°x
  18. Two supplementary angles are in the ratio 3:7. Find the smaller one
  19. Find the complement66°x
  20. Find the supplement60°x

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

Sigma Prep · sigmaprep.io/worksheets

Name

Angle RelationshipsAnswer keyVersion 1

Date Period

Find each angle.

  1. Find the complementx85
  2. Find the supplement172°x8
  3. Two supplementary angles are in the ratio 1:4. Find the smaller one36
  4. Find the complement63°x27
  5. Find the supplement175°x5
  6. Two complementary angles are in the ratio 2:7. Find the smaller one20
  7. Find the complement37°x53
  8. Find the supplement31°x149
  9. Two complementary angles are in the ratio 1:2. Find the smaller one30
  10. Find the complement67°x23
  11. Find the supplement37°x143
  12. Two complementary angles are in the ratio 1:5. Find the smaller one15
  13. Find the complement69°x21
  14. Find the supplement40°x140
  15. Two supplementary angles are in the ratio 2:7. Find the smaller one40
  16. Find the complement20°x70
  17. Find the supplement82°x98
  18. Two supplementary angles are in the ratio 3:7. Find the smaller one54
  19. Find the complement66°x24
  20. Find the supplement60°x120

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

How to do these

Find the complement of 37

  1. Complementary angles add to 90.
  2. 90 minus 37.

The answer is 53.

Where students go wrong

Swapping the two words. Complementary is the smaller total, 90, and supplementary is 180. A quick check: a complement only exists for an angle under 90.

Also called complementary angles, supplementary angles or angle pairs.

What you can put on this worksheet

Complementary angles
Find the complement 40
Supplementary angles
Find the supplement 80
Two angles in a ratio
Two supplementary angles are in the ratio 1:8. Find the smaller one 20

Questions about these worksheets

Yes. Every angle relationships 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.

Pre-Algebra is usually taken around 7th or 8th 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 angle relationships 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 three 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 3: complementary angles, supplementary angles and two angles in a ratio. Tick as many as you want and set how many of each, or let it spread them evenly.

Swapping the two words. Complementary is the smaller total, 90, and supplementary is 180. A quick check: a complement only exists for an angle under 90.