大师作文网已知弦长20.5和拱高1.8求弧长
来源：学生作业帮 编辑：大师作文网作业帮 分类：数学作业 时间：2024/09/21 17:29:47
已知弦长20.5和拱高1.8求弧长
已知弦长L=20.5和拱高H=1.8求弧长C?
弧半径为R,弧所对的圆心角为A.
R^2=(R-H)^2+(L/2)^2
R^2=R^2-2*R*H+H^2+L^2/4
2*R*H=H^2+L^2/4
R=H/2+L^2/(8*H)
=1.8/2+20.5^2/(8*1.8)
=30.084
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((20.5/2)/30.084)
=39.84度
=39.84*PI/180
=0.69535弧度
C=A*R
=0.69535*30.084
=20.919
弧半径为R,弧所对的圆心角为A.
R^2=(R-H)^2+(L/2)^2
R^2=R^2-2*R*H+H^2+L^2/4
2*R*H=H^2+L^2/4
R=H/2+L^2/(8*H)
=1.8/2+20.5^2/(8*1.8)
=30.084
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((20.5/2)/30.084)
=39.84度
=39.84*PI/180
=0.69535弧度
C=A*R
=0.69535*30.084
=20.919