The elements of plane geometry, Τόμος 1

ABCD AC is equal alternate angle altitude angle ABC angle ACB angle AFG angle BAC angle EDF angles are equal angles equal Apply base bisector bisects called centre coincide common Constr construct construct a triangle diagonal difference distance divided draw equal to CD exterior angle extremities fall figure formed four Geometry given angle given point given straight line greater half Hence identically equal interior intersect isosceles triangle join less Let ABC locus meet middle point opposite angles opposite sides pair parallel parallelogram perpendicular plane point equidistant polygon Post Prob produced projection Prove quadrilateral radius rectangle contained remainder right angles segments shew side AB side AC square on AC straight line drawn surface THEOR Theorem triangle ABC twice the rectangle unequal vertex vertices whole