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

in the side of the perspective square, and draw

p c

parallel to X Y, cutting the perspective circle in

c

.

Fig. 33.

COROLLARY.

It is obvious that if the points P′, Q′, R, etc., by which the circle is divided in [Fig. 32.], be joined by right lines, the resulting figure will be a regular equilateral figure of twenty sides inscribed in the circle. And if the circle be divided into given unequal parts, and the points of division joined by right lines, the resulting figure will be an irregular polygon inscribed in the circle with sides of given length.

Thus any polygon, regular or irregular, inscribed in a circle, may be inscribed in position in a perspective circle.