Perspective and geometrical drawing adapted to the use of candidates for second and third-class teachers' certificates . Fig. 77. 112 DRAWING. Let A, B, C be the given points; join them to form a tri-angle; with centre A, and distance greater than half of AC,describe an arc; with centre C and same distance, describe anarc to cut former; join points of section of arcs; this line willpass through the centre of the circle; draw similar arcs onAB, and join points of section to meet in D, the centre; thena circle drawn with centre D, and distance DA, will passthrough A, B and C respectively. (Fig.
Perspective and geometrical drawing adapted to the use of candidates for second and third-class teachers' certificates . Fig. 77. 112 DRAWING. Let A, B, C be the given points; join them to form a tri-angle; with centre A, and distance greater than half of AC,describe an arc; with centre C and same distance, describe anarc to cut former; join points of section of arcs; this line willpass through the centre of the circle; draw similar arcs onAB, and join points of section to meet in D, the centre; thena circle drawn with centre D, and distance DA, will passthrough A, B and C respectively. (Fig. 77.) 1^0, 10,—To find the centre of a whole or part of a Fig. 78. Let BACD be a circle or arc; draw any two chords AB,CD, and draw arcs EF and GH, bisecting the chords, respec-tively; join EF and HG and produce them to meet in K;then K will be the centre, and if K and D be joined, KDwill be a radius, and a circle may be thus described with itwith the centre thus found. (Fig. 78.) GEOMETRICAL DRAWING. 113 iVo. 11.—To draw a tangent to a given circle a) from apoint in the circumference.
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Keywords: ., bookcentury1800, booksubjectgeometricald, booksubjectperspective
