梯形ABCD中,AB∥DC,对角线AC,BD交与O,过O作MN∥DC交AD于M,交BC于N 求证:OM/AB+ON/BC的值AB是上底,DC是下底,A,D都在左边

问题描述:

梯形ABCD中,AB∥DC,对角线AC,BD交与O,过O作MN∥DC交AD于M,交BC于N 求证:OM/AB+ON/BC的值
AB是上底,DC是下底,A,D都在左边