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.

The Elements of Perspective arranged for the use of schools and intended to be read in connection with the first three books of Euclid · 第 48 / 91 题