AE=AM=BN=1.75
CE=CD
AC:AB=CD:BN
(CE-AE):1.25=CD:1.75
(CD-1.75):1.25=CD:1.75
1.75(CD-1.75)=1.25CD
1.75CD-3.0625-1.25CD=0
0.5CD=3.0625
CD=6.125≈6.1m
AE=AM=BN=1.75
CE=CD
AC:AB=CD:BN
(CE-AE):1.25=CD:1.75
(CD-1.75):1.25=CD:1.75
1.75(CD-1.75)=1.25CD
1.75CD-3.0625-1.25CD=0
0.5CD=3.0625
CD=6.125≈6.1m