(1)
CD=CA+AB+BD
=AB+AB+1.5AB
=3.5AB
∴ CD是AB的3.5倍.
(2)
BC=CA+AB
=AB+AB
=2AB
又CD=3.5AB
有 AB=CD/3.5
即 CD=2CD/3.5
=4CD/7
∴BC是CD的7分之4.
(1)
CD=CA+AB+BD
=AB+AB+1.5AB
=3.5AB
∴ CD是AB的3.5倍.
(2)
BC=CA+AB
=AB+AB
=2AB
又CD=3.5AB
有 AB=CD/3.5
即 CD=2CD/3.5
=4CD/7
∴BC是CD的7分之4.