《明史·志·卷八》
将半径六十度八七五自乘，得三干七百零五度七六五六二五，用矢六度与之相除，得六百一十七度六十三分为股弦的和，再加矢六度，共六百二十三度六十三分，就是大圆直径。
置半径六十零度七五自之，得三千七百零五度七六五六二五，以矢六度而一，得六百一十七度六十三分为股弦和，加矢六度，共六百二十三度六十三分为大圆径。
The square of the radius of sixty degrees and eight tenths and seventy-five is three thousand seven hundred and five degrees and seventy-six thousand five hundred and sixty-two and a half. Dividing this by the chord of six degrees gives six hundred and seventeen degrees and sixty-three minutes for the sum of the hypotenuse and chord. Adding the chord of six degrees again gives a total of six hundred and twenty-three degrees and sixty-three minutes, which is the diameter of the great circle.