 An angle measures the amount of turn, so how much has been turned? They're measured in degrees which are written like this. A quarter turn is 90 degrees, a half turn, so turning on a straight line is 180 degrees, and a whole turn is 360 degrees. Angles come up everywhere in life, which is why we need to learn about them. The slope on roofs so that rain and snow can slide off. Pilots use angles to make sure they stay on course. They also use angles for taking off and landing to make sure they don't come in too steep. In construction and by animators. Angles of different sizes have different names. Acute angles are less than 90 degrees. Think of small cute puppies. Cute, acute means small. Right angles are exactly 90 degrees like in squares. Notice how right angles are always shown with a box rather than a curve. That's only for 90 degrees. Next up we have obtuse angles. These are bigger than 90 degrees but smaller than 180. They go from right angles to straight lines at 180. So less than 90 is acute, exactly 90 is right, and from 90 to 180 is obtuse. To a straight line at exactly 180. So then last up are angles bigger than 180 degrees. These are called reflex angles. An easy way to remember the smallest is acute, then obtuse and the biggest is reflex is just to know that they go in alphabetical order. A-O-R. Be careful which angle you're being asked for. This is obtuse, but this one is reflex. An acute and obtuse and acute and reflex. Here are a few questions for you to do. Pause the video, answer them and click play when you're ready. Did you get them right? So there we have the names of different types of angles. Just remember, acute, obtuse, reflex go in alphabetical order. Please like and share our videos with your friends. If you have any questions, comment below.