Manual of Euclid, Elements I, II, III.

ABDC AC is equal adjacent angles angle ABC angle BAD angle contained angle equal Annotations centre chord circle ABC circumference Conclusion.—Therefore construct Corollary 2.-If diameter double the square draw equal angles equal right lines equal to CD external angle fore given circle given point given rectilinear angle given right line gnomon greater segment hypotenuse internal and opposite intersection isosceles triangle less let fall let the common lines be drawn lines equal locus middle point opposite angles parallel parallelogram perpendicular produced Proof Prop PROPOSITION prove quadrilateral rectangle contained remaining angle right angles right line AB right line AC right line joining right-angled triangle semicircle square of AC square of AO Statement.-Let tangent touches the circle triangle ABC twice the rectangle unequal vertex vertical angle