The first six books of the elements of Euclid : with a commentary and geometrical exercises ; to which are annexed a treatise on solid geometry, and short essays on ancient geometrical analysis, and the theory of transversals (1861)
Lardner, Dionysius, 1793-1859 · London : Print. for Taylor and Walton · leaf 124
that perpendicular to the point of con-tact, it cuts the circle. Part 1°.—For, if it be possible* let B G, which meets the circleagain, be perpendicular to A B, and draw C G. Because in the triangle C B G the side G C is equal to C B,the angle C B G is equal to C GB (V, Book I.), and thereforeeach… … Pari. 2°.—Let H F be perpendicular to AB, and let E Bline drawn from a point between it and the circle,which, if it be possible, does not cut the circle. Because the angle C B F is a right angle,C B E is acute; draw C I perpendicular to B E,and it must fall at the side of the angle C B E. Then in…
Geometry
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