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# Measuring angles using a protractor 2

Sal measures several angles with a protractor. Created by Sal Khan.

## Want to join the conversation?

• How are angles used in everyday life?
• Angles can be used for measuring several objects with a wedge or just anything. They can also be used for building and constructing big things and objects
• Is there a angle greater than 360 degrees?
• Yes, there can be angles greater than 360 degrees.A angle greater than 360 degrees is called a reflex angle.
• There are countless special names for angles, but many of these are not important at this level of study. Here are the main ones you should know.
Acute angle: less than 90°
Right angle: 90°
Obtuse angle: between 90° and 180°
Straight angle: 180°
Reflex angle: between 180° and 360°
Perigon angle or Full angle: 360°
Oblique angle: any angle other than 0° or a multiple of 90°
Complementary angles: two angles that add up to 90°
Supplementary angles: two angles that add up to 180°
Explementary or conjugate angles: two angles that add up to 360°.
Interior angle (meaning one): the angle inside of a polygon formed by the meeting of two sides.

Interior angle (meaning two): any of the four angles formed between two lines where a transversal intersects them.

Exterior angle (meaning one): an angle on the outside of a polygon formed by a side and its extended adjacent side.

Exterior angle (meaning two): any of the four angles formed by a transversal that are not between the two lines the transversal intersects. In other words, one of the outside four angles a transversal creates.

Adjacent angles: two angles which share one common side and share a common vertex.

Vertical angles: the angles on opposite sides of two intersecting lines

There are a variety of other terms for various kinds of pairings of angles.
• Thank you for posting this because i always had problems remembering my angle
• How are angles used in everyday life?
• You can use them to find distances and heights of other objects. You can also use them to describe the motion of objects with a periodic or predictable pattern such as a child playing on a park swing. There are many more applications than just these.
• I think the protractor is a smart idea.It helps me allot,but who invented the protractor?
• Hello hangap 🙌

Its great that the protractor helps you a lot, It helps me too!!
A protractor was invented by "Joseph Huddart"

A little about Joseph Huddart :-
He was a U.S naval captain meaning, He was the captain of the U.S navy.
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Hope this helped!!
• Does the angle have to be 100% accurate or can it just be really close
• Teachers typically accept the answer as long as its in a certain range of degrees (ex: from 90-95)
• How do you measure a circle?
• There is also a tool like a double protractor shaped like a full circle so you can just use that too.
• How can angles be used in real life?
• Angles are used in many parts of real life. If someone tells you to go two miles to an intersection and take the left 45 degree turn, you'd need to understand what they meant.

Beyond that, there are many careers that use angles such as: drafting, architecture, engineering, fire fighting, carpentry, map making, flying, just to name a few.