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

在几何量量中一直以弓高弦法量圆弧半径值。

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.

为了降低量误差,提出了对圆弧直径量的法。