十万火急!AD、BC交于O,AB=CD,AD=BC.求证OB=OD,OA=OC
已知,如图,AC,BD交于O点,且OA=OC,OB=OD.求证:AB平行CD,AD平行BC.
已知:如图,直线AD与BC交于点O,OA=OD,OB=OC.求证:AB∥CD.
如图,AD和BC相交于点O,OA=OD,OB=OC.求证AB平行DC?
AB与CD交与点O,且OE⊥AD OF⊥BC OE=OF OA=OB 求证OC=OD
已知:如图,AB平行CD,AD与BC相交于点O,且OA=OD.求证OB=OC
如图所示,在梯形ABCD中,AB‖DC,AD=BC,AC与BD交于点O,求证:OA=OB,OD=OC
如图所示,在梯形ABCD中,AB//DC,AD=BC,AC与BD交于点O,求证OA=OB,OD=OC
如图AD,BC相交于点O,且OA=OC,OB=OD EF过点O分别交AB,CD于点E,F且∠AOE=∠COF.求证OE=
(1)如图,四边形ABCD中,AD=BC,AB=CD,求证:OA=OC,OB=OD
AB与CD相交于点O OA=OD OB=OC 求证:AD‖CB
已知AB与CD相交于点O,且OA=OD,OB=OC,求证AD//CB
如图所示,AC、BD相交于点O,且OA=OC,OB=OD.求证:AD∥BC.