. The New York coach-maker's magazine. b b). Then join the points A, B and C by thelines A B and B C. The triangle ABC thus formed willbe the one desired. LXXV. If it were desired to deploy the triangle 20 THE NEW YORK COACH-MAKERS MAGAZINE July, upon the vertical plane, the line a b could be taken forthe axis around which to turn it. Now a C being perpen-dicular to a b, the points A and C would then fall on aline a C, drawn from point a perpendicular to a b, and insuch a manner that the result would be a A7 equal to a A,and a CJ equal to a C. On joining the points A;, bJ andCyby the lines A6a
. The New York coach-maker's magazine. b b). Then join the points A, B and C by thelines A B and B C. The triangle ABC thus formed willbe the one desired. LXXV. If it were desired to deploy the triangle 20 THE NEW YORK COACH-MAKERS MAGAZINE July, upon the vertical plane, the line a b could be taken forthe axis around which to turn it. Now a C being perpen-dicular to a b, the points A and C would then fall on aline a C, drawn from point a perpendicular to a b, and insuch a manner that the result would be a A7 equal to a A,and a CJ equal to a C. On joining the points A;, bJ andCyby the lines A6and bC, the triangle Ay ftC wouldbe the desired triangle. LXXVI. In thecases of deploying that we have effected,the triangle had one of its sides upon the horizontal let us consider the case where the triangle is inspace, beyond the planes of projection, and following aposition perpendicular to one of those planes ; for instance,to the horizontal plane. Then the projection of the triangleon that plane will be a straight Let c a b, c a1 b (fig. 52) be the horizontaland vertical projections of the triangle that we intendto deploy first on to the horizontal plane. The plane ofthe triangle must be supposed to be extended until its pro-jectants meet the horizontal plane. The figure of thatplane will be projected on the vertical plane by the rec-tangular trapeze cc0 bab\ and on the horizontal plane itwill be traced by the line c b, which is but the horizontalprojection of the triangle. On taking the line c b as theaxis, each point of the triangle, in the movement aroundc b, which remains fixed, will describe the arc of a circlethe plane of which is perpendicular to that line (art. 72).It therefore now remains to be known where each pointunder consideration will pierce the horizontal plane. The points in question are the angles (c, c1), (a, a), (b, bJ) of the triangle. The arcs of circles described bythese points have for radius the vertical lines perpendic-ular to the
Size: 1444px × 1730px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1850, bookidnewyorkcoach, bookyear1858
