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圆弧计算:弦长1m,弦高0.8m,求弧长?弦长3.76m弦高1.14m,求弧长?加分

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圆弧计算:弦长1m,弦高0.8m,求弧长?弦长3.76m弦高1.14m,求弧长?加分
圆弧计算:弦长1m,弦高0.8m,求弧长?弦长3.76m弦高1.14m,求弧长?加分
弦长L=1m,弦高H=0.8m,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*H*R+H^2+L^2/4
2*H*R=H^2+L^2/4
R=H/2+L^2/(8*H)
=0.8/2+1^2/(8*0.8)
=0.55625m
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((1/2)/0.55625)
=128.022度
C=PI*R*A/180=PI*0.55625*128.022/180=1.243m
弦长L=3.76m弦高H=1.14m,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*H*R+H^2+L^2/4
2*H*R=H^2+L^2/4
R=H/2+L^2/(8*H)
=1.14/2+3.76^2/(8*1.14)
=2.12m
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((3.76/2)/2.12)
=124.928度
C=PI*R*A/180=PI*2.12*124.928/180=4.623m
再问: 若R>H,则:C=PI*R*A/180 若R