生活中到处可见道路、房屋、山川、桥梁……,在这些大自然的杰作与人类的创造物中,蕴含着大量的平行线与相交线.在这一章里,我们将发现平行线与相交线的一些特性,并探索两条直线平行的条件. 一、学习目标: ★在具体情境中了解余角、补角、对顶角等概念,知道等角的余角相等、等角的补角相等、对顶角相等的性质. Roads, houses, mountains and rivers, bridges, etc. are everywhere in life. In these natural masterpieces and human creations, there are a large number of parallel lines and intersecting lines. In this chapter, we will find parallel lines and intersections. Some characteristics of the line, and to explore the conditions of the two straight lines. First, learning objectives: ★ In the specific situation to understand the concept of complement angle, supplementary angle, right angle, etc., know that the equal angle is equal, the angle of the supplementary angle Equal, equal to the vertex angle nature.