Perspective and geometrical drawing adapted to the use of candidates for second and third-class teachers' certificates . Fig. 98. GEOMETRICAL DRAWING. 127 Let B, C be the foci and A, given point on the curve; joinBA and CA and produce them to D and F; bisect the angleBAD by AK, and the angle DAF by AG. Then will KA bea tangent and GA a perpendicular or normal to it, at thepoint of contact, A. (Fig. 98.) (b) From an external Fig. 99. Let A be an external point; draw major axis BC, and onit describe the semi-circle BFC; draw a tangent AF to thecircle at F; draw FE perpendicular to BC, cu

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Perspective and geometrical drawing adapted to the use of candidates for second and third-class teachers' certificates . Fig. 98. GEOMETRICAL DRAWING. 127 Let B, C be the foci and A, given point on the curve; joinBA and CA and produce them to D and F; bisect the angleBAD by AK, and the angle DAF by AG. Then will KA bea tangent and GA a perpendicular or normal to it, at thepoint of contact, A. (Fig. 98.) (b) From an external Fig. 99. Let A be an external point; draw major axis BC, and onit describe the semi-circle BFC; draw a tangent AF to thecircle at F; draw FE perpendicular to BC, cutting curve inG; join AG, which will be a tangent, to the curve. (Fig. 99.) No, 26.—To draw an oval of a given width. Let AB be the given width; bisect it in C, and on it describethe circle ADB; draw CD at right angles to AB; with centreB and distance BA describe curve AE; similarly describe us DRAWING. curve BI; join BD and AD, and produce them to meet curvein E and F; with centre J) and distance DE describe curveEE, completing the oval. (Fig. 100.)

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Keywords: ., bookcentury1800, booksubjectgeometricald, booksubjectperspective