证明两直线平行的若干策略甘肃省华池县一中路李明证明两直线平行是数学竞赛中考查几何知识的重要形式之一．本文试图综合出数学竞赛中证明两直线平行的若干策略．现将其列举如下，仅供参考互．利用“同位角相等（或内错角相等，或同旁内角互补），则两直线平行”’例１在... Several strategies to prove the parallelism of two straight lines Li Ming, Yizhong Road, Huachi County, Gansu Province, proved that the parallelism of two lines is one of the important forms of geometric knowledge examination in mathematical competitions. This article attempts to synthesize some strategies to prove the parallelism of the two lines in the math contest. It is listed below for reference only. Using “the same isotropic angle (or the internal angle is equal, or complementary to the internal angle), then the two lines are parallel” example 1 in...