1.问题的提出苏课版七年级数学下P35习题12:如图,小明从点A出发,沿直线前进10米后向左转30°,再沿直线前进10米,又向左转30°……照这样走下去,他第一次回到出发地A点时,一共走了多少米.解答这个题目由多边形外角和公式,可以得到小明走过的路线为正十二边形的周长,因此小明共走了120m.为了得到正多边形向左转的角度最大值为120°,而且是360的约数,我们提出如下问 1. Question Presentation Sub-lecture Textbook for Grade 7 Mathematics P35 Exercise 12: As shown in the figure, Xiao Ming starts at point A, moves 30 meters along the straight line and then 30 ° to the left, then moves 10 meters along the straight line and turns 30 ° to the left ... ... go on like this, when he first returned to the starting point A, a total of how many meters go.To answer this question from the polygon outer corner and the formula, you can get Xiaoming’s route is the circumference of the regular twelve polygons , So Xiao Ming walked a total of 120m. In order to get the regular polygon to the left of the maximum angle of 120 °, and is a divisor of 360, we asked the following questions