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三侧棱两两垂直的三棱锥被同学们戏称为“墙角子”,因它和墙角子形状类似而得名.它有这样几点性质:性质1顶点在底面上的射影是底面三角形的垂心.性质2顶点到底面距离的倒数的平方等于三侧棱长的倒数的平方和.性质3三侧面面积的平方和与底面面积的平方相等.下面对这三个性质加以
The three-sided, two-vertical, triangular pyramids are nicknamed “wall corners” by students. They are named because they resemble the shape of a wall corner. It has several properties: Nature 1 The apex of the apex is the base of the triangle. Property 2 The square of the reciprocal of the distance from the apex to the base is equal to the sum of the squares of the reciprocals of the lengths of the three sides. Property 3 The square sum of the areas of the three sides is equal to the square of the area of the bottom. These three properties are added below.