3.若等腰梯形的两底之差等于一腰长,则它的腰与下底夹角为( )A.30° B.45° C.60° D.75°

问题描述:

3.若等腰梯形的两底之差等于一腰长,则它的腰与下底夹角为( )
A.30° B.45° C.60° D.75°