Boeken  Boek 41  42 van 42 over IF magnitudes, taken jointly, be proportionals, they shall also be proportionals.... 
IF magnitudes, taken jointly, be proportionals, they shall also be proportionals when taken separately ; that is, if two magnitudes together have to one of them the same ratio which two others have to one of these, the remaining one of the first two shall... The Elements of Euclid with Many Additional Propositions and Explanatory Notes  Pagina 51 door Eucleides  1860 Volledige weergave 
