Measure angles with a protractor
A protractor is a tool your child will use again and again in geometry, and later in science, art, and design. Measuring and drawing angles also builds a sense of what 30, 90, or 150 degrees looks like, which helps them spot a wrong answer. Next they add angles, find missing ones, and sort shapes by their angles, work that continues into 5th grade and middle school.
In this video, your child will learn to measure angles in degrees with a protractor.
The lesson stops at each question for your child's answer.
Three problems, each a little harder
Each problem is worked step by step. Your child will solve the last one before Bobby shows how.
Example 1
How many degrees is this angle?
Example 2
How many degrees is this angle?
Your child's turn
How many degrees is this angle?
The three key steps
- 1Put the center on the vertex.
- 2Count up from the zero on a ray
- 3Check: 45°, 90°, 180°
Mistakes to listen for
- 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.
The lesson shows every step, so your child sees why it works. Read our parent's guide to measuring and drawing angles with a protractor →
Is your child ready to practice what they've learned?
Bobby's Math Club offers unlimited practice for free.
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More 4th grade Measurement & Data, with questions your child answers along the way.
Questions parents ask
Does my child need an account to watch?
No. You can watch this on any device at any time. If your child would like to practice measuring and drawing angles with a protractor, and you'd like parent-friendly reports on your child's progress and growth, you can join Bobby's Math Club for unlimited free practice.
What happens when my child answers a question?
A right answer gets a cheer, and the lesson carries on. If your child isn't sure, they can tap "I don't know yet", and Bobby gives the answer and shows another example. Nothing is scored or stored.
Is this the same lesson that's on YouTube?
Yes. Here, the lesson stops at each question and waits for your child to answer. On YouTube, each question stays on screen for a few seconds, and then the lesson plays on.
Where can I learn more?
There's a short, kid-friendly lesson like this one for every Pre-K to 5th grade math skill, all in our video library. Our parent's guide to measuring and drawing angles with a protractor has more on where kids get stuck and how you can help at home. In the club, your child practices at just the right level, about five minutes a day, and you get parent-friendly reports as they grow. Learn more about how it works →
Practice measuring and drawing angles with a protractor
Questions at your child's level, about five minutes a day, on measuring and drawing angles with a protractor and whatever PK-5 skills they need to develop. Unlimited practice, free forever.
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