已知弦長(zhǎng)L=818,弦高H=779,求圓心角A和弧長(zhǎng)C
R^2=(R-H)^2+(L/2)^2
R^2=R^2-2*H*R+H^2+(L/2)^2
2*H*R=H^2+(L/2)^2
R=H/2+L^2/(8*H)
=779/2+818^2/(8*779)
=496.869
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((818/2)/496.869)
=110.8度
=110.8*PI/180
=1.9339弧度
C=A*R
=1.9339*496.869
=906.889
已知弦高H=779,半徑R=819,求圓心角A和弧長(zhǎng)C
L=2*(R^2-(R-H)^2)^0.5
=2*(819^2-(819-779)^2)^0.5
=1636.045
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((1636.045/2)/819)
=174.4度
=174.4*PI/180
=3.044弧度
C=A*R
=3.044*819
=2492.9
已知弦長(zhǎng)L=818,半徑R=819,求圓心角A和弧長(zhǎng)C
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((818/2)/819)
=59.919度
=59.919*PI/180
=1.0458弧度
C=A*R
=1.0458*819
=855.45