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## Basic geometry and measurement

### Course: Basic geometry and measurement>Unit 3

Lesson 5: Measuring angles

# Measuring angles review

Review measuring angles with a protractor, then try some practice problems.

## Measuring angles

Angles are measured in degrees. We can use a protractor to measure how many degrees an angle is.
Example:
Measure the following angle in degrees:
An angle is drawn that is smaller than a right angle.
First, we line up the dot on the center of the protractor with the vertex of the angle.
An angle is drawn that is smaller than a right angle. The angle is placed on top of a protractor. One ray points to 90 and the other points to 160 degrees, moving clockwise.
Next, we rotate the protractor so that the 0, degrees mark lines up with one side of the angle.
An angle is drawn that is smaller than a right angle. The angle is placed on top of a protractor. One ray points to 0 and the other points to 70 degrees, moving clockwise.
Finally, we read the protractor to see where the other side lines up.
The angle is 70, degrees.

## Practice

Problem 1
• Current
Measure the angle in degrees.
degrees

Want to try more problems like this? Check out this exercise.

## Want to join the conversation?

• how can we move the triangle so we get in the right space so we can get it right?
• If you click and hold on the protractor, you can drag it wherever you want. You will need to drag the protractor so that the dot in the middle of the straight side is exactly over the "vertex" of the angle (this is the point where the two lines of the angle meet).

Once you have the protractor in the right place, you can unclick. Then just click and drag the green arrow to rotate the protractor around. You will want to rotate the protractor until the part that says "0" lines up with one side of the angle.

Now you can tell what the measure of the angle is by seeing what number the other side of the angle passes through on the protractor.

Hope this helps!
• OMG I figured it out! lol Question, is it possible to kind of eye the measurement? Where you dont use any tools you just look at the angle?
• I think you can.
• What job we need to use this?
• Engineer, Programmer, most if not all of the trades, and probably a few more.
• sometimes it is easy to guess the angle measure so why use protractors
• sometimes we need to use protractors to find the exact answer of degrees.
• that was a lot easier after just looking at it
• I know but when you do it it is not easy
• The questions are very easy and simple. Could you do a version for older kids?