A treatise on special or elementary geometry (1877)
Olney, Edward, 1827-1887, Olney, Edward, 1827-1887. Elements of trigonometry, plane and spherical · New York : Sheldon · leaf 144
o angleshavetheir sides respectively perpendicular toeach other, the angles are either equal orsupplementary. Dem,—Let BA be perpendicular to EF orto EF, and BC to ED; then is ABC = DEF.For, through B draw BO and BN, respectivelyparallel to ED and EF; then by the precedingjTropositions NBO = DEF,… … 124 ELEltENTABY PLANE GEOMETEY. OF TRIMGLES. PROPOSITION VI. 284. Theorem.—Tiuo tricmgles ivMcli have hoo sides and theincluded angle of one equal to two sides and the included angle of theother, each to each, are equal, Dem.—Let ABC and DEF be two triangles, havingAC = DF, AB = DE, andangle A =…
Geometry · Trigonometry
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