Davies, Charles, 1798-1876 · New York and Chicago, A. S. Barnes and company · leaf 25
ACD+BCD=ADC+BDCthat is, the angle ACB=ADB. Now, the two triangles ACB and ADBhave two sides and the included angle ofthe one equal to two sides and the in-cluded angle of the other, each to each: hence, the remainingangles will be equal (Th. iv): consequently, the angle CABis equal to BAD, and the… … THEOREM IX. If one side of a triangle is produced, the outward angle is greater than either of the inward opposite angles. Let ABC be a triangle, having the sideAB produced to D : then will the outwardangle CBD be greater than either of theinward opposite angles A or C. For, suppose the side CB to…
Geometry · Plane trigonometry
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
