Acute, Right or Obtuse? is a free printable Grade 4 maths worksheet on classifying an angle against a right angle, aligned to Common Core standard 4.MD.C.5. It prints 7 questions with an answer key on its own sheet of paper, in 25 versions, 24 of them with different questions, so no two pupils in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.
4.MD.C.5
Work out each answer.
LessonPrint · 4.MD.C.5 · Set 1 · free to copy for classroom use
Set 1. Prints on its own sheet.
It practises classifying an angle against a right angle — 7 questions for Grade 4, all on Common Core 4.MD.C.5: Understand what an angle is. The instruction to pupils is “Work out each answer”, and the answer key follows on the next sheet.
CCSS.MATH.CONTENT.4.MD.C.5 — 4.MD.C.5, in the Measurement & Data domain for Grade 4. The published standard reads: “Recognize angles as geometric shapes that are formed wherever two rays share a common endpoint, and understand concepts of angle measurement.” The worksheet assesses that standard rather than a paraphrase of it.
Acute, Right or Obtuse? is written for Grade 4, typically ages 9-10. It is one of the sheets on 4.MD.C.5, so it suits any pupil working at that standard — including older pupils revisiting it and younger ones working ahead.
Yes. All 7 answers are generated from the same problems as the questions, so the key cannot drift out of step with the sheet. It starts on a fresh sheet of paper, after the questions, so it is not handed out with the class by accident.
25 versions, of which 24 ask genuinely different questions — this skill does not have 25 distinct questions to give, so the rest reorder them and no two pupils still share a paper. Set 1 downloads all 25 as one PDF.
Yes. Acute, Right or Obtuse?, its answer key and its 25 versions are free to print and photocopy for your own class, with no account, no email capture and no subscription at the download step. Please do not resell them or republish them as your own.
Yes — “What an Angle Measures” is a 50-minute Grade 4 plan for 4.MD.C.5, timed section by section, with the misconceptions to expect and an exit ticket. Acute, Right or Obtuse? is the practice that follows it.
Understand what an angle is.
Teaching this next? What an Angle Measures is the 50-minute plan for it, with the misconceptions to expect.
Last reviewed 2026-09-05. Aligned to 4.MD.C.5 of the Common Core State Standards for mathematics.