The elements of Euclid : viz, the first six books, together with the eleventh and twelfth : the errors, by which Theon, or others, have long ago vitiated these books, are corrected, and some of Euclid's demonstrations are restored : also, The book of Euclid's data, in like manner corrected (1834)
Euclid, Euclid, Simson, Robert, 1687-1768 · Philadelphia : Desilver & Thomas · leaf 139
roportional: andparallelograms that have one angle of the one equal toone angle of the other, and their sides about the equalangles reciprocally proportional, are equal to one ano-ther. Let AB, BC be equal parallelograms, which have the angles atB equal, and let the sides DB, BE be placed in the…
Mathematics, Greek · Geometry · Trigonometry
Internet Archive · California Digital Library · Public Domain Mark 1.0. Free to use for anything.