You have :
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DE arc = ( pi ) ( AD ) ( 2.36 radians / 2 pi radians ) = ( 2/3 ) ( AB ) ( 2.36 radians / 2 )
DE arc = ( 2/3 ( AB ) ( 1.18 radians )
BC arc = ( pi ) ( AB ) ( 1.18 radians / 2 pi radians )
BC arc = ( AB ) ( 0.59 radians )
BC arc / DE arc = ( AB ) ( 0.59 radians ) / ( 2/3 ) ( AB ) ( 1.18 radians )
BC arc / DE arc = ( AB ) ( 0.59 rad ) / ( 2/3 ) ( AB ) ( 1.18 rad )
BC arc / DE arc = ( 3/2 ) ( .59 rad / 1.18 rad ) = 3/4 <-------
