Science and art drawing : complete geometrical course ; consisting of plane and solid geometry, orthographic and isometric projection, projection of shadow's the principles of map projection, graphic arithmetic and graphic statics (1895)
Spanton, J. Humphrey (John Humphrey) · London : Macmillan · leaf 201
E as centre, and EB as. radius, draw the semicircle BFC. Make the angle BCF equal to i8o PRACTICAL PLANE GEOMETRY the angle ACB, and produce the line till it meets the semicirclein F. Join BF. The triangle BFC is then similar to thetriangle ABC. By repeating this construction we obtain asuccession… … Fig. 316. As each triangle with its curve forms a similar figure, it isevident that the curve must form a constant angle with itsradius vector, i.e. the line radiating from C, and the portion ofthe curve accompanying each triangle, must also bear a constantproportion to the length of its radius…
Geometrical drawing
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