Euclid, Books 1-4

ABCD alternate angle ABC angle ACB angle BAC base bisect centre chord circle ABC circumference common Constr Construction converse depends describe diagonals diameter difference divided double draw drawn Edition equal Euclid EXERCISES exterior angle externally extremities falls figure four given circle given point given straight line greater half inscribed interior intersect isosceles triangle join length less line joining locus manner meet method middle point opposite angles opposite sides parallel parallelogram passes pentagon perpendicular point of contact possible produced Proof Prop Proposition prove quadrilateral radii radius rectangle contained regular respectively rider right angles segment sides square square on AC taken tangent theorem third touch triangle ABC twice the rectangle vertical angle whole