The Elements of Perspective / arranged for the use of schools and intended to be read in connection with the first three books of Euclid

by John Ruskin

[Footnote 26: ] The demonstration is in [Appendix II. Article III].] [Return to text]

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][PROBLEM XVII.]

TO FIND THE DIVIDING-POINTS OF A GIVEN INCLINED LINE.

Fig. 46.

Let P, [Fig. 46.], be the vanishing-point of the inclined line, and V the vanishing-point of the relative horizontal.

Find the dividing-points of the relative horizontal, D and D′.

Through P draw the horizontal line X Y.

With center P and distance D P describe the two arcs D X and D′ Y, cutting the line X Y in X and Y.

Then X and Y are the dividing-points of the inclined line.[Footnote 27] ]