BOOK. I.

SPHERICAL GEOMETRY.

35

be great circles, the triangles D E Vj D I V,have the angles VED, (—LIE) =DIV, andthe angle V, and side 13 V common, and yetare unequal.

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PROBLEM VIII.

From a given point F on the sphere,to draw a great circle O P C perpendi-cular to another given circle D C.—(PI.i. fi. 2.)

Through O, the pole of the given circleand the given point P, draw the great circleO P C, (P. I. B. I.) meeting the circumferencein C, and the thing is done.

The demonstration is evident, from C. II.P. V. and D. 41.

THEOREM XV.

If through the nearest poles P, Z, oftwo equal circles D VI, LK.C, a great

E 2