论文部分内容阅读
一、用园规绘制五角星 1.在1点过圆心作垂直线,将圆的直径均分为6段; 2.过2作水平线与圆周相交; 3.作交叉线4过第4等分点与圆相交: 4.作线5即得。二、用作图法求任意一段圆弧线——AB的长度(近似值) 1.先求圆心(按两切线的垂直线相交可得); 2.联结A1为该圆的半径; 3.作垂直线3; 4.用作图法将弧线AB分为4等份; 5.通过弧线的第一等分点作半径,延长与垂直线交于P点; 6.以P为圆心,PB为半径作弧与3线交于B′,即得AB′=AB。
1. Use a garden gauge to draw a five-pointed star 1. Make a vertical line at the center of circle at 1 o’clock and divide the circle’s diameter into 6 segments; 2. Make the horizontal line intersect with the circle; 2. Make the cross line 4 over the 4th. Point and circle intersection: 4. For line 5 that is. Second, as a map method to find any section of the arc - AB length (approximation) 1. The first to find the center of the circle (according to the intersection of two tangent vertical lines available); 2. A1 connection for the radius of the circle; 3. For Vertical line 3; 4. Use as a map method to divide the arc AB into 4 equal parts; 5. Use the first half of the arc to make a radius, extend and intersect the vertical line at point P; 6. Take P as the center, PB is an arc with a radius and 3 lines intersect at B′, ie, AB′=AB.