Ellipse construction, ContinuedConjugateThe conjugate diameter method of ellipse construction uses conjugatediameterdiameters to project a circle and through a series of tangents, plot points onmethodthe circumference of the ellipse.To construct an ellipse using conjugate diameters, use this table;StepAction1Given two conjugate diameters (AB and DE) with C as a center,use the distance from C to A as a radius to draw a circle with C asthe center.2Draw line (GF) perpendicular to AB and passing through C.3Draw lines connecting points D and F and points G and E.4Select any point (X) along AB and draw a line (PQ) parallel to DEand RS parallel to FG.5Determine at least five points to each quadrant. For larger ellipses,plot more points. The more points plotted the more accurate theellipse circumference.6Lightly sketch the outline of the ellipse. Darken the ellipse usingfrench curves.Figure 2-50 illustrates the conjugate diameter method of ellipse construction.Figure 2-50.—Theconjugate diametermethod.Continued on next page2-52

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