Beman, Wooster Woodruff, 1850-1922, Smith, David Eugene, 1860-1944 · Boston, Ginn & company · leaf 307
edral crystal has its trihedral angles replaced by planes, how many faceshas the new crystal ? How many edges ? vertices ? Is Eulers theoremsatisfied ? 624. How many planes of symmetry and how many axes of sym-metry has a regular hexahedron ? octahedron ? f 290 SOLID GEOMETRY. [Bk. VII. Pkopositiox… … A B Given a parallelepiped with diagonals AG, BH, CE, DF. To prove that (1) the diagonals are concurrent at 0, the mid-point of each;(2) AG2 + BH2 + CE2 + BE2 = AB2 + BC2 + Proof. 1. v BF= and II BR, Why ? .-.DBFH is a. CJ. Why? 2. .. ED and BH bisect each other at 0. § 100, cor. 2Similarly, BH and…
Geometry
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