问题
填空题
▱ABCD中,AB=3,AD=5,E为AB中点,在BC上取一点F,使△DCF∽△DAE,则BF=______.
答案
如图所示:
∵ABCD中,AB=3,AD=5,E为AB中点,
∴AE=1.5,
∵△DCF∽△DAE,
∴
=CF AE
,即CD AD
=CF 1.5
,解得CF=0.9,3 5
∴BF=5-0.9=4.1.
故答案为:4.1.
▱ABCD中,AB=3,AD=5,E为AB中点,在BC上取一点F,使△DCF∽△DAE,则BF=______.
如图所示:
∵ABCD中,AB=3,AD=5,E为AB中点,
∴AE=1.5,
∵△DCF∽△DAE,
∴
=CF AE
,即CD AD
=CF 1.5
,解得CF=0.9,3 5
∴BF=5-0.9=4.1.
故答案为:4.1.