$Angle relationships: stretch: math worksheet for Grade 9, page 1 preview$

Math worksheet · Mathematics

Angle relationships: stretch · Grade 9

Use angle facts: complementary, supplementary, vertical and triangle sums. 16 problems at a stretch level for Grade 9, with an answer key for grown-ups.

Grade 9 · ages 14 to 15
Hard
25 to 35 minutes
2 pages
Free

The answer key is a separate page for grown-ups. Sign in to download it.

Make another one like this

The 16 problems on the sheet

Directions: Find each missing angle.

1. Triangle angles 12° and 37°. Third angle:
2. Triangle angles 24° and 49°. Third angle:
3. Interior angle sum of a hexagon:
4. Triangle angles 29° and 54°. Third angle:
5. Complementary to 71°:
6. Interior angle sum of a octagon:
7. Supplementary to 112°:
8. Interior angle sum of a decagon:
9. Supplementary to 65°:
10. Triangle angles 76° and 101°. Third angle:
11. Triangle angles 22° and 47°. Third angle:
12. Supplementary to 86°:
13. Supplementary to 114°:
14. Triangle angles 45° and 70°. Third angle:
15. Supplementary to 79°:
16. Triangle angles 61° and 86°. Third angle:

What your child practices

Your child practices math for Grade 9 with this math worksheet.

Grades and ages: Grade 9, ages 14 to 15
Time: About 25 to 35 minutes
Subject: Mathematics
Level: Hard for Grade 9
Answer key: Yes, for grown-ups who sign in
Printing: 2 pages, US Letter or A4, low-ink option
Updated: October 15, 2026

How to use it

Try the first question together so the format is clear. Then let your child work through the rest, showing their thinking on the page. It is one of the harder sheets for Grade 9, best once the basics of the topic are secure. Its 2 pages split well across two sittings.

An answer key comes with it as a separate page that grown-ups download after signing in.

Tip for grown-ups: Check the first three problems together before your child carries on alone; most mix-ups show early.

Done on paper? A grown-up can record it on the child's page in PlayOwl; downloading alone doesn't count as finished.