People used to measure the radius of nonplastic circular by the length of bowstrings in the geometric calculation .

在几何一直以弓高弦长等方法非整形圆弧半径值。

In order to reduce the error in the calculation, this article raises a measure method to the radius of nonplastic circular arc which basis on the principle of geometry.

为误差,提出对非整形圆弧直径的方法。