Cutting radius of a quarter circle of the two angle; two perpendicular angle to the line
Translated by Google
No. 3
Vertical line intersecting the two into the corner, right angle at right. "Rites to Paul's official," "Liu Yue nine the number of" clear a Summary of Justice: "Where the triangle, there must be the trilateral ... ... Ciffa Yan, number right angle also." Qingjiang Fan "State of Qing scholarship, Dai Zhen" : "people today are eight lines with the triangle method, the triangle for pythagorean ... ... No right angle, you should almost moment." Lao She, "two horses" paragraph 5: "Mr. nag seated posture, positive and small guan'er see the same boss rules: children are the backbone of the back and a chair at right angles, holding hands in the lap them the strength. "