设半径长r米,
r²=(3÷2)²+(r-0.35)²,
解得r=23.725/7≈3.39,
圆心角α=2arcsin(3÷2/r)≈52.536°,
弧长=2πr(α/360°)=3.11(米)
弦长L=3米,拱高H=0.35米,设弧半径为R,弧所对的圆心角为A,弧长为C,则:
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)
=0.35/2+3^2/(8*0.35)
=3.389米
A=2*ARC SIN[(L/2)/R]
=2*ARC SIN[(3/2)/3.389]
=52.54度
C=π*R*A/180=π*3.389*52.54/180≈3.1米