Perspective and geometrical drawing adapted to the use of candidates for second and third-class teachers' certificates . m it j near angle 2 to left. Draw and as before, find M. Take K 2 to leftof X, and G 2 to left of K; bisect GK in H j draw GR, HSand KT at right angles to , and b in length; join TP 3, and with centre T and distance TP describe arcPN, cutting HS in N : join KT and KR : KRT will be theplan of the triangle. Through N draw UNQ parallel to RT, cutting GR in Uand KT in Q; with centre K and distance KQ describe arcQL, cutting in L; and with same centre
Perspective and geometrical drawing adapted to the use of candidates for second and third-class teachers' certificates . m it j near angle 2 to left. Draw and as before, find M. Take K 2 to leftof X, and G 2 to left of K; bisect GK in H j draw GR, HSand KT at right angles to , and b in length; join TP 3, and with centre T and distance TP describe arcPN, cutting HS in N : join KT and KR : KRT will be theplan of the triangle. Through N draw UNQ parallel to RT, cutting GR in Uand KT in Q; with centre K and distance KQ describe arcQL, cutting in L; and with same centre and distanceKT describe arc TY, cutting in Y. Join G ,H and K ; and join also LM and Y]\I to cutK in E and C. Through E draw EAF, and throughC draw CDB, each parallel to , and cutting H in Aand D respectively; join BA and AC : then ABC will be thetriangle required. For CK = KY = KT = 5, and EC = LA =QT = NS = height of triangle, and EK = KL==KQ. HenceAD = NS and AH = HN. But since triangle is isosceles, GHis made equal to HK; hence BD = DC = GH = HK, then CA= NT = NR = BA. (Fig. 23.). Example S,—Draw an equilateral triangle, each side 4, oneside on ground plane parallel to ; triangle placed _|_ toground plane and touching 3 to right. Draw , and , and find M. Take point D 3to R., and B 3^ to right of D ; on DB describe the equilateraltriangle DGB. Bisect DB in E, join EG; through G drawFH parallel to , and through D, B draw DF, BH parallelto EG, cutting FH in F, H. Join B , draw EM, DM,cutting B C. Y. in N and A. With centre B and distance BHdescribe arc HK, cutting BK, a perpendicular on , at K; THE TRIANGLE. 43 join K Through A and N draw parallels to BK, meet-ing K in L and C; join AC, CB. Then ABC is thetriangle required. For LA = CIvT = KB = BH = EG = altitudeof the triangle; and AN = NB = DE = EB, and AB = DB =
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Keywords: ., bookcentury1800, booksubjectgeometricald, booksubjectperspective
