4th Grade · Measurement & Data
4.MD.C.6: Measure angles in degrees with a protractor
4.MD.C.6 is a 4th grade Common Core math standard in Measurement & Data. Here’s what it really covers, and how you can help your students learn it.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
The standard
Measure angles in whole-number degrees using a protractor. Sketch angles of specified measure.
In plain words
Measure angles in degrees with a protractor.
Sample questions from student practice
These questions from Bobby's Math Club are the kinds of questions your students will see. You can try answering them to see what a student might see.
Question 1 of 3
Nia sketches a right angle. What is a quick way to check her sketch without a protractor?
- Fit the corner of a sheet of paper into it
- Check that one of its rays lies flat
- Check that its two rays are the same length
Where students can get stuck
- Reading the wrong row of numbers, so a 50-degree angle is recorded as 130 degrees.
- Placing the protractor's edge or corner at the vertex instead of its center point, which throws every reading off.
- Guessing a reading when a ray is too short to reach the scale, instead of drawing it longer.
Effective teaching strategies
- Model how to place the protractor’s center point on the vertex and one ray on the zero line, then read the scale that starts at 0 on that ray.
- Ask students to decide whether an angle is less or more than 90° before reading, so they catch a 50° angle recorded as 130°.
- Have students sketch a 70° angle by marking the vertex and 70 on the scale, and draw the rays long enough that a classmate can read the scale.
Units that teach this standard
Find where 4.MD.C.6 lands in the program you teach. Each unit has a guide written for families. Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence.
Bridges in Mathematics
enVision Mathematics
Everyday Mathematics
Go Math!
i-Ready Classroom Mathematics
Illustrative Mathematics
Math Expressions
Reveal Math
Don’t see your curriculum? Contact Bobby and we’ll see if we can help!
Share it with families
Families can read Measuring and drawing angles with a protractor for a plain-language look at this skill, with three questions to try together and ideas for helping at home.
Help every student practice measurement and data at home
In Bobby's Math Club, students practice at just the right level, with a hint when they need one, a clear explanation after every question, and kid-friendly videos. Unlimited practice is free for every family.
See how it works for teachers
Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.