【摘要】 平面几何的许多命题可以推广到立体几何中，本文就三个平几命题加以推广，并给以证明．更多还原

【Abstract】 A lot of inequalities in plane geometry may extend to solid geometry.The inequalities in solid geometry are often limited in plane to deal with,or changed into plane geometry to solve and it can also be proved by anlysis.this article will extend the three plane geometrical propositions.更多还原