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.

为降低测量误差,提非整形圆弧径测量的方法。

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

何量测量中一以弓高弦长等方法测量非整形圆弧半径值。