# Angles

There are three types of angles, and so, an angle is formed whenever two lines meet. So, right here, we have an angle, we have an angle right here, and we have an angle right here.

So, the three types of angles are acute, right, and obtuse. So, right here, we have a right angle, and so the angle measure of a right angle is exactly 90°.

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Question 1 of 5

1. How many degrees form one complete sweep through a circle like noon to midnight on a clock?

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2. How many degrees sweep the half circular arc between directly east and directly west?

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3. How many degrees form a right angle like noon to 3pm on a clock?

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4. How many degrees make up the four corners of a rectangle?

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5. How many degrees make up the three corners of a triangle?

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The following transcript is provided for your convenience.

And so, a square is made up four right angles, and so, this line right here is perfectly vertical, this line is perfectly horizontal, and so, what we call perpendicular to each other. Now, if the angle measures less than 90°, we call it acute. So, this is an acute angle or an acute angle. And so, a good way to remember this is to think about a cute, little angle. Like, a cute, little angle.

So, think about it being small, because of a lot of times, people think that animals that are really small are cute, so this angle right here is small, and so, we call it a cute angle. It’s kind of – it may sound a little bit silly, but it’s a good way to remember it.

And then, we have this right here, which is an obtuse angle, and so, the obtuse angle has an angle measure greater than 90°. And so, you just look at these and realize that this angle measure is bigger than this one.

And so, basically, the measure of an angle is how close the two lines are together. So, there are these two lines are close to each other, these lines are little farther apart, and then these lines are far apart.

And so, notice right here that ‘ob’ in obtuse is also like ‘ob’ in obese, which means overweight. And so, you can think about obtuse meaning big or enormous, and so, that’s another little trick to remember it.

So, again, the three types of angles are right, acute, and obtuse. And so, for all angles that measure less than 90°, we call it an acute angle. For all angles that measure greater than 90°, we call it an obtuse angle. And then, for those angles that have a measure of exactly 90°, we call it a right angle.