摘要把紧密相连的圆环构成的圆盘以渐开线展开成等面积的直角三角形，得出了较为直观的由周长和半径表示的圆面积公式。
The disk, which is composed of continuous annuluses, can expand equivalent trangle by asymptotice line. We can obtain the circular area which is visually expressed by circumference and radius.
本文介绍了一种用半径为r的圆弧绘制多节等径直角弯头展开曲线的方法——圆弧法。
In this paper, a method-ARC method is introduced, by which the development chart can be drawn, of multiple-piece, equal-diameter and right-angled elbows with the radius as the arc of r.
应用推荐