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⏰ 4th grade math · Measure, Time & Money

Measure angles

Under 90 degrees is acute. Over 90 and under 180 is obtuse. 180 degrees is a straight angle.

Worked example

What kind of angle is this? (Compare it to a square corner.)
Answer: right
A right angle is a square corner, 90 degrees.

For grown-ups: Angles as turns; measure with a protractor; additive angles. Below: three problems to try with the worked answers, and a free printable sheet. Children can practise the same skill as a game, with no sign-up and no ads.

  • CCSS 4.MD.C.5–7
What this practises, for teachers

Practices angles as turns; measure with a protractor; additive angles (4.MD.C.5–7). A printable sheet with its answer key, worked answers on the page, no accounts.

▶ Practise it

For your class

🖨️ Printable sheet and key

Try three

  1. What kind of angle is this? (Compare it to a square corner.)
    Show the answer and how
    Answer: acute
    An acute angle is smaller than a right angle (a square corner).
  2. Which picture shows an acute angle?
    ABC
    Show the answer and how
    Answer: Picture C
    An acute angle is smaller than a right angle (a square corner).
  3. Which picture shows an obtuse angle?
    ABC
    Show the answer and how
    Answer: Picture C
    An obtuse angle is bigger than a right angle but smaller than a straight line.

Before and after

Learn first: Area and perimeter rules (4th)

Comes next: Convert units, more steps (5th)

Name: ____________________Date: ____________Score: ____ / 12

Measure angles (4th grade)

  1. What kind of angle is this? (Compare it to a square corner.)
  2. What kind of angle is this? (Compare it to a square corner.)
  3. What kind of angle is this? (Compare it to a square corner.)
  4. Which picture shows an acute angle?
    ABC
  5. Which picture shows a straight angle?
    ABC
  6. An angle measures 149 degrees. What kind of angle is it?
  7. Which picture shows an acute angle?
    ABC
  8. Which picture shows an obtuse angle?
    ABC
  9. What kind of angle is this? (Compare it to a square corner.)
  10. An angle measures 147 degrees. What kind of angle is it?
  11. Which picture shows an acute angle?
    ABC
  12. Which picture shows a right angle?
    ABC

Answer key

  1. right
  2. obtuse
  3. acute
  4. Picture A
  5. Picture B
  6. obtuse
  7. Picture B
  8. Picture B
  9. straight
  10. obtuse
  11. Picture A
  12. Picture B

More 4th grade skills: all 4th grade math skills, or every grade at math skills.