The five-pointed star has five inner angles and five outer angles. The tip of the regular pentagram is 36 degrees, and the twist is 108 degrees. A pentagram can be divided into five identical isosceles right triangles and a regular pentagon. The formula for calculating the polygon internal angle is (n-2) × 180 (n is greater than or equal to 3, and n is an integer). It can be calculated that the sum of the internal angles of the Pentagon is (5-2) × 180 = 540, so the degree of each angle of the Pentagon is: 540 ÷ 5 = 108.

It is impossible to draw a five-pointed star accurately with bare hands. In some paintings, the inaccurate five-pointed star gives people a relaxed feeling, but in national flags, national emblems and trademarks, the five-pointed star must be completely accurate, and the proportion of any line segment of the five-pointed star must be equal to the golden section. This requires the help of tools. In fact, it is difficult to draw by hand, and it is easy to draw with tools. You can draw with a ruler and compasses without scales, and you can draw with a ruler. The five-pointed star drawn by the following method is absolutely accurate.