《立体几何》课本在推导锥体体积时,首先推导了三梭锥的体积公式,采取的方法是给三棱锥添设辅助体,使之成为一个三棱柱。从而得出三棱锥的体积是三棱柱体积的三分之一。这一处理问题的方法在解某些立几题时经常用到,掌握这种方法对培养学生的空间想象能力和分析问题的能力大有裨益。 Stereo geometry textbook in the derivation of the cone volume, the first deduction of the volume of three shuttle cone formula, the method is to add auxiliary body to the triangular pyramid, making it a triangular prism. It follows that the volume of the triangular pyramid is one-third of the volume of the triangular prism. This method of dealing with problems is often used when solving certain elicitation problems. To grasp this method is of great help in cultivating students' ability of spatial imagination and problem analysis.