1, direct dial number
This method is suitable for a small number of corner points, but it is more troublesome for a large number of corner points, and sometimes it can't be counted and one is missed.
2. Use the formula
Formula for calculating angles: number of angles = number of sides × (number of sides-1)÷2. The number of angles is related to the number of rays drawn from a point.
The law of counting angles is as follows: when the number of counting edges is n, the total angle degree is continuously added from 1 to n-1; When the number of small angles is divided by n, the total angle degree is continuously added to n from 1. For example, there are three sides and the number of angles is 2+ 1. There are four sides and the number of angles is 3+2+ 1. There are five sides, the number of angles is 4+3+2+ 1, and so on.
Extended data:
Brief introduction of angle
In geometry, an angle is a geometric object composed of two rays with a common endpoint. These two rays are called the edges of an angle, and their common endpoint is called the vertex of the angle. The general angle is assumed to be in Euclidean plane, but it can also be defined in Euclidean geometry. Angle is widely used in geometry and trigonometry.
Euclid, the father of geometry, once defined an angle as the relative inclination of two non-parallel straight lines in a plane. Proclos thinks that angle may be a trait, a quantifiable quantity, or a relationship. Oldham thinks that an angle is a deviation from a straight line, and Cabus of Antioch thinks that an angle is a space between two intersecting straight lines. Euclid thinks that an angle is a relationship, but his definitions of right angle, acute angle or obtuse angle are quantitative.
The size of the angle has nothing to do with the length of the side, but depends on the opening degree of both sides of the angle. 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.