课时一　基本立体图形同学们 ,我们在日常生活中所见到的物体 ,虽然形状各异 ,但它们大多数是由一些基本立体图形构成 .这些基本立体图形主要是 :棱柱、棱锥、圆柱、圆锥和球 .下面我们分别简单介绍它们的特征 .(1)棱柱棱柱有上下两个底面 ,这两个底面是由形状相同的多边形构成 A basic three-dimensional graphics lesson classmates, although the shapes of the objects we see in everyday life are different, most of them are composed of some basic three-dimensional graphics. These basic three-dimensional graphics are mainly: prisms, pyramids, cylinders, cones And the ball. Here we briefly introduce their characteristics. (1) Prismatic prisms have two upper and lower bottoms, these two bottoms are formed by the same shape of the polygon