梯形作为一类特殊的四边形有其一些特殊的性质,受文[1]的启发,笔者又得到梯形与两条腰有关的两组性质,兹介绍如下,以飨读者.图1性质1如图1,四边形ABCD是梯形,AB∥DC,两条腰AD、BC延长后交于O,过O分别引AB、AC的平行线交直线AC、BD、AB、CD于E、F、G、H,M为一条对角线AC的中点,直线AF、BM交于I,直线DM、CF交于J,则(1)EO=OF;(2)AF∥DM,BM∥CF;(3)点I、J在直线OG上,且I、J分别是OG、OH的中点. Trapezoid as a special type of quadrilateral has its own special properties. Inspired by [1], the author obtains two sets of trapezoidal and two waist-related properties, which are introduced as follows. 1, Quadrilateral ABCD is a trapezoid, AB∥DC, two lumbar AD, BC extension of the intersection at O, O were cited AB, AC parallel lines AC, BD, AB, CD in E, F, G, H (1) EO = OF; (2) AF // DM, BM // CF; (3) AF // DM, BM // CF; Points I, J are on the straight line OG, and I, J are the midpoints of OG, OH, respectively.