In the case of a single vertex, assuming that there are n rays including the outermost two rays, the number of angles of large and small * * * is:1+2+3+...+(n-2)+(n-1).

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Note that it is not added to n, but to (n- 1). For example, * * * has eight rays, so there are angles: 1+2+3+4+5+6+7 = 28 angles.

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In the case of a multi-vertex lane, that is, a polygon (such as a triangle), you only need to count the number of angles of each vertex of the polygon according to the above method, and then add the number of angles of each vertex of the polygon to get the total number of angles.

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. The angle has nothing to do with the size of the angle, but with the amount of light at the same point.

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