已知一弧长为C=20πcm,其所对圆心角为A=150°,则此弧所在圆的半径为R?
A=150°
=150*π/180
=5*π/6弧度
R=C/A
=(20π)/(5*π/6)
=(120π)/(5*π)
=120/5
=24cm
此弧所在圆的半径为24cm.