在求几何体的体积时,我们有时会遇到不能直接套用体积公式的情形,这时可通过分割或补形把此几何体分割为几个基本图形或拼补为一个基本图形,以便适用公式,“能割善补”是解几何题的基本方法之一．例1 已知斜三棱柱的一个侧面的面积等于S,这个侧面与它所对的棱的距离是a,求这 In the calculation of the volume of the geometry, we sometimes encounter the situation that we cannot directly apply the volume formula. In this case, we can divide the geometry into several basic shapes or make up a basic shape by dividing or complementing, in order to apply the formula. 3. One of the basic methods for solving a geometric problem is to cut it. Example 1 It is known that the area of ​​one side of an oblique triangular prism is equal to S, and the distance between this side and the rib it faces is a, find this