1, the definition and basic concepts of angle

An angle is a graph formed by two rays sharing a starting point. You can measure the angle to indicate its size, and the unit is degrees (degrees). The complete angle is 360 degrees. In addition, the angle can also be measured in radians (rad).

2, the method of measuring angle

There are several methods to measure the angle. The most common is the cost. The right angle is 90 degrees, the obtuse angle is greater than 90 degrees and the acute angle is less than 90 degrees. Another method is to use the minutes and seconds of the angle system: 1 degree equals 60 minutes, and 1 minute equals 60 seconds.

3. Calculation of angle degrees

In plane geometry, for two given rays, we can calculate the degree of angle by geometric method. For example, the degree of a right angle is always 90 degrees, while all three internal angles of an equilateral triangle are 60 degrees.

4. Calculation of angle radian

In addition to measuring angles in degrees, radians can also be used. Radian is a unit used to measure the angle of a circle, which belongs to dimensionless unit. A complete circumferential angle is equal to 2π radians.

5. Application of Angle

Angle is widely used in mathematics and physics. In geometry, angle is the basis of studying shapes and figures. In trigonometry, angles are used to calculate trigonometric functions, such as sine, cosine and tangent. In physics, angles are used to describe the rotation and rotation of objects.

Summary:

Angle is measured in degrees, which represents the size of a graph formed by two rays sharing a starting point. Degree is a common method for measuring angles. In the degree system, a complete angle is 360 degrees, which can be further subdivided into minutes and seconds. Another commonly used angle measurement method is radian, which is used to measure the circumferential angle.

Angle has important applications in mathematics, geometry, trigonometry and physics. Angle measurement not only has important applications in mathematics and physics, but also plays a role in daily life.

For example, the navigation system uses the angle to indicate the direction, and we have experienced the change of day and night in the rotation and transfer of the earth. Even the angle formed by fingers plays an important role in daily communication and expression. Angle measurement is the basis for us to understand and describe space, position and direction, which is of great significance for scientific research and technical application.