A right angle is an angle of 90 degrees. It is relative to a quarter of a circle (that is, a quarter of a circle), and two right angles are equal to a half angle (180).

An acute angle less than a right angle is called an acute angle.

Oblique angle, the angle greater than right angle and less than right angle is called obtuse angle.

Flat angle, the light rotates around its endpoint. When the starting edge and the ending edge are on the same straight line and in opposite directions, the angle formed is called a straight angle.

Fillet, the angle formed by light rotating around its endpoint, is called fillet.

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The size of the angle has nothing to do with the length of the side; The size of an angle depends on the degree to which both sides of the angle are open. The bigger the opening, the bigger the angle. Conversely, the smaller the opening, the smaller the angle.

In dynamic definition, it depends on the direction and angle of rotation. Angles can be divided into acute angle, right angle, obtuse angle, right angle, rounded corner, negative angle, positive angle, upper angle, lower angle and 0 angle, which are 10 respectively. An angle measuring system in degrees, minutes and seconds is called an angle system. In addition, there are secret system, arc system and so on.

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Baidu encyclopedia-right angle

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Baidu encyclopedia-rounded corners

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Baidu encyclopedia-jiao