如图,∠ACB=∠ADC=90°,BC=a,AC=b,AB=c,要使△ABC∽△CAD,只要CD等于( ) A.b2c B.b2a C.abc D.a2c
问题描述:
如图,∠ACB=∠ADC=90°,BC=a,AC=b,AB=c,要使△ABC∽△CAD,只要CD等于( )
A.
b2 c
B.
b2 a
C.
ab c
D.
a2 c
答
假设△ABC∽△CAD,
∴
=CD AC
,AC AB
即CD=
=AC2 AB
,b2 c
∴要使△ABC∽△CAD,只要CD等于
,b2 c
故选A.