问题补充:
如图,在梯形ABCD中,AD∥BC,AB=DC,过点D作AC的平行线DE交BA的延长线于E,AC交BD于F.
(I)求证:△AFB≌△DFC;
(II)求证:DE•DC=AE•BD.
答案:
答案:分析:(I)四边形ABCD为等腰梯形,可由∠ABD=∠DCA,∠BAC=∠CDB.又AB=DC,证出△AFB≌△DFC
(II)先证出△ADE∽△CBD,再得出DE•DC=AE•BD.
时间:2018-10-20 01:02:11
如图,在梯形ABCD中,AD∥BC,AB=DC,过点D作AC的平行线DE交BA的延长线于E,AC交BD于F.
(I)求证:△AFB≌△DFC;
(II)求证:DE•DC=AE•BD.
答案:分析:(I)四边形ABCD为等腰梯形,可由∠ABD=∠DCA,∠BAC=∠CDB.又AB=DC,证出△AFB≌△DFC
(II)先证出△ADE∽△CBD,再得出DE•DC=AE•BD.