如图,梯形ABCD,对角线AC与BD相交于O,设AD=a,BC=b,△AOD,△AOB,△BOC,△COD的面积分别为S
1、S
2、S
3、S
4,则下列各式中错误的是( )
A.
=
B.
=
C.
=
D. S
1+S
3=S
2+S
4
∵AD∥BC,∴△AOD∽△COB,∴S1S3=a2b2,∴A正确;同理,∵△AOD∽△COB,∴ODOB=OAOC=ab,∵△AOD与△AOB等高,∴S1:S2=AD:BC=a:b,B正确.同理C也正确,由B,C可知S1=abS2,S3=baS4,∴S1+S3=a2+b2ab(S2+S4)...