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What Kind of Triangle? is a free printable Grade 4 math worksheet on naming a triangle from its largest angle, aligned to Common Core standard 4.G.A.2. It prints 9 questions with an answer key on its own sheet of paper, in 25 versions that each ask different questions, so no two students in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.

Set 18 of 25 · the same problems every time you open this link.

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Set 1 has all 25 in a single PDF. All 25 sets ask different questions.

What Kind of Triangle?

4.G.A.2

NameDate

Write acute, right or obtuse.

1.A triangle has angles of 45°, 45° and 90°. Is it acute, right or obtuse?
2.A triangle has angles of 65°, 25° and 90°. Is it acute, right or obtuse?
3.A triangle has angles of 35°, 90° and 55°. Is it acute, right or obtuse?
4.A triangle has angles of 165°, 10° and 5°. Is it acute, right or obtuse?
5.A triangle has angles of 10°, 20° and 150°. Is it acute, right or obtuse?
6.A triangle has angles of 115°, 20° and 45°. Is it acute, right or obtuse?
7.A triangle has angles of 135°, 25° and 20°. Is it acute, right or obtuse?
8.A triangle has angles of 80°, 90° and 10°. Is it acute, right or obtuse?
9.A triangle has angles of 40°, 55° and 85°. Is it acute, right or obtuse?

LessonPrint · 4.G.A.2 · Set 18 · free to copy for classroom use

Answer key — What Kind of Triangle?

Set 18. Prints on its own sheet.

  1. 1.right
  2. 2.right
  3. 3.right
  4. 4.obtuse
  5. 5.obtuse
  6. 6.obtuse
  7. 7.obtuse
  8. 8.right
  9. 9.acute

Last reviewed 2026-09-05. Aligned to 4.G.A.2 of the Common Core State Standards for Mathematics.