文［１］给出一个定理：对任意三角形，存在等周等积的矩形．本文试考虑类似问题在三维空间的推广，并得出以下定理１　对体积为Ｖ，表面积为Ｓ的多面体，存在等体积等表面积长方体的充要条件是　　　　Ｓ≥６３Ｖ２．（１）证明　（必要性）若体积为Ｖ，表面积为Ｓ的长方体存 A theorem is given in [1]: For an arbitrary triangle, there is an equal-area equal-area rectangle. In this paper, we try to consider the similar problems in the three-dimensional space, and draw the following theorems 1 for a volume V, surface area S polyhedron, there is equal volume and other surface area cuboids necessary and sufficient conditions is S ≥ 63V2. (1) Proof (Necessity) If the volume is V, a rectangular solid with a surface area of ​​S