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## 4th grade

### Course: 4th grade>Unit 12

Lesson 2: Measuring angles

# Constructing angles review

Review constructing angles with a protractor, then try constructing some of your own.

## Constructing angles

We can use a protractor to help us construct an angle of a given amount of degrees.
Example
Construct a 65, degrees angle.
To make a 65, degrees angle, we move the middle dot of the protractor to the vertex (where the 2 rays connect) of the angle.
A protractor shows points plotted at 160 and 180 degrees. Rays go out from a vertex at the protractor's center and through each point.
Next, we line up one of the rays on the 0, degrees line of the protractor.
A protractor shows points plotted at 0 and 180 degrees. Rays go out from a vertex at the protractor's center and through each point.
We then move the other ray around until it is lined up with the 65, degrees measurement on the protractor.
A protractor shows points plotted at 0 and 65 degrees. Rays go out from a vertex at the protractor's center and through each point.
The angle will look like this when the measurement is 65, degrees. Note: The angle can be rotated in any direction, but the angle between the two rays must look like this.
An angle is formed by two rays extending out from a common point. The size of the angle is the same as in the previous image.
Want to learn more about constructing angles? Check out this video.

## Practice

Problem 1
• Current
Construct a 40, degrees angle.

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

## Want to join the conversation?

• i love angle things. could you make more exercises?
(58 votes)
• Of course they would dude!You could donate to make it more convincing though.
(8 votes)
• It really makes me feel stupid when I get these questions wrong.
(23 votes)
• You have no reason to feel stupid! This can be hard for some people and there is absolutely no shame in asking questions! I am here for you, I know math can be challenging but we have this beautiful community in Khan Academy to support you. Telling people that you don't understand is a very brave thing to do.
(43 votes)
• Who thinks we need angles all he time in real life? Vote if yes.Reply if no!
(40 votes)
• Angles are absolutely everywhere. For instance take the doornob of a door.How much does it turn? Than Answer shall come as an angle.

So you see, we are all surrounded with angles.Actually Everything around us has geometry or Mathematics in it.
(14 votes)
• Super easy angles i mean right?
(19 votes)
• Yep!The protractors were a bit glitching at the start.
(10 votes)
• This is really easy right? I only *just started* doing angles with protractors and I seemed to know
(14 votes)
• This is a great way of learning because the schools are not open. Khan academy is such a great way to learn stuff. It is easy to understand what they are trying to teach
(8 votes)
• This is not great for me thou I'm having tons of glitches and some stuff wont respond I'd rather have paper
(3 votes)
• will we actually need these things when we become an adult yes or no
(5 votes)
• I believe you WILL need these things when you become an adult, particularly if you decide to become an architect or engineer.
But there will also be times when you will need to deal with angles in your every day life.

Keep at it!! You can do it!!
(9 votes)
• i love this! mind making more?
(7 votes)
• I want to try more problems . will I get them?
(7 votes)
• could you make more of these please and thank you
(6 votes)