X Tables
manipulatives

Protractors

Use protractors to measure and draw angles accurately.

Quick answer

A protractor is a tool used to measure and draw angles. You can use it to find out how big an angle is, or to draw an angle of a specific size.

Learning outcome

By the end of this page, you will be able to measure and draw angles using a protractor accurately. Success signs:
  • You can place the protractor correctly on an angle
  • You can read the angle measurement from the protractor
  • You can draw an angle of a given size
  • You can explain why it's important to use a protractor

Why this matters

Angles are everywhere around us! When you turn your head to look at something, you make an angle. When you open a door, you make an angle. When you play football, you kick the ball at an angle. Using a protractor helps you measure these angles exactly, which is important in many jobs like building houses, making toys, or flying planes. It's also useful for art, crafts, and even for understanding how your body moves.

How it works

A protractor is a special tool shaped like a semi-circle with numbers around the edge. To use it:
  1. Place the protractor so that its centre point is exactly on the corner of the angle
  2. Align one side of the angle with the zero line on the protractor
  3. Read the number where the other side of the angle crosses the edge of the protractor
  4. Make sure you read from the right scale (inner or outer) depending on which side you started from

Examples you can see

Let's imagine you're drawing a garden. You want to make a corner for a flower bed. You can use a protractor to make sure your corner is exactly 90 degrees (a right angle). Here's how you would measure a corner:
  1. Put the protractor's centre point on the corner of the angle
  2. Align one side of the corner with the zero line
  3. Look at where the other side meets the edge of the protractor
  4. If it meets at 90, then it's a right angle
Try this with a book. Open it up and look at the corner. Place your protractor on the corner and see what angle it makes. Most books have corners that are 90 degrees. Another example is when you're playing with a compass. If you're drawing a circle, you can use a protractor to make sure each part of your circle is the same size. If you want to make a 60-degree angle, you would place your protractor, line up one side with the zero line, and then mark where 60 degrees is on the edge.

Try it as a mini adventure

Adventure: The Angle Explorer You are a young explorer who has found an ancient map with a secret treasure. The map shows three paths that meet at a point, and you must measure the angles to find the correct way to go.
  1. First path: The angle is 45 degrees
  2. Second path: The angle is 135 degrees
  3. Third path: The angle is 180 degrees
You need to use your protractor to measure each angle on the map. Then, you must draw the correct path that makes a 90-degree angle. This will help you find the treasure! To do this:
  1. Find a flat surface to draw on
  2. Draw a point where the paths meet
  3. Use your protractor to draw each path at the correct angle
  4. Look for the path that makes a right angle (90 degrees)
This adventure will help you practice measuring and drawing angles with your protractor.

Common mistakes

  • Mistake: Placing the protractor incorrectly on the angle
    Why it happens: Not putting the centre point exactly on the corner of the angle
    Fix: Make sure the small hole or dot on the protractor is exactly on the angle's corner
  • Mistake: Reading the wrong scale on the protractor
    Why it happens: Not checking which scale to use (inner or outer)
    Fix: Look at which side of the angle you started from, and use the matching scale
  • Mistake: Not lining up one side of the angle with the zero line
    Why it happens: Thinking the angle is measured from the middle of the protractor
    Fix: Always align one side of the angle with the zero line before reading the measurement
  • Mistake: Drawing an angle that is too big or too small
    Why it happens: Not counting carefully or not using the correct side of the protractor
    Fix: Count the degrees carefully and double-check your measurements

Parent and carer guide

To help your child with protractors:
  1. Start with simple angles like 90 degrees and 45 degrees
  2. Practice placing the protractor correctly on the angle corner
  3. Ask your child to explain how they are measuring the angle
  4. Encourage them to check their work by measuring the same angle twice
  5. Use real-world examples like doors, books, or toys to practice
  6. Remember that it's okay to make mistakes - they help us learn!
  7. Be patient and keep the practice fun and exploratory
When your child is learning to use a protractor, they might feel frustrated. That's normal! Keep the atmosphere light and encourage them to try again. You can also help by doing the same activity together.

Practice questions

  1. What is the angle shown on the protractor if one side is at 0 degrees and the other side is at 60 degrees?
  2. How would you draw a 120-degree angle using a protractor?
  3. What is the angle between the hands of a clock at 3 o'clock?
  4. If you measure an angle and it shows 150 degrees, what kind of angle is it?
  5. What is the angle shown when one side is at 0 degrees and the other side is at 90 degrees?
Answers:
  1. 60 degrees
  2. Place the protractor on the corner, align one side with the zero line, and mark where 120 degrees is on the edge
  3. 90 degrees (a right angle)
  4. An obtuse angle (more than 90 degrees but less than 180 degrees)
  5. 90 degrees

FAQ

What is a protractor used for?

A protractor is used to measure and draw angles. It helps you find out how big an angle is or to make sure you draw an angle of a specific size.

How do I know which scale to read on a protractor?

Look at which side of the angle you started from. If you started from the left side, read the outer scale. If you started from the right side, read the inner scale.

Can I use a protractor to measure any angle?

Yes, you can measure angles from 0 to 180 degrees using a protractor. This covers all the angles you will need in your everyday life and school.

What should I do if my protractor doesn't have a clear centre point?

Find the middle of the protractor's straight edge and place that point on the corner of the angle. This is where the centre point should be.

How can I practice using a protractor at home?

You can practice by measuring angles in your house, like the corners of your room, or by drawing angles of different sizes using your protractor.