54 PRGPOSITIONES 



2. Primum problema hoc efto : Datis radio 



circuli BD et arcuum AB , BC chordis, Inuenire 

 chordam AC arcus AC ex prioribus arcubus datis 

 compofiti. Ponatur radius DE=BD=:r, Chorda 

 AB=:r^ chorda BC~<^. chorda quaefita ACzz.r.Du- 

 dla diametro BE lineisque AE ct CE , erunt anguli 

 BAE et BCE redi , adeoque per Pythagorae theo- 

 rema fiet linea AE=:V(^rr-a~)et CE~Vi^r--l,') 

 Exinde per theorema Ptolomaei habebitur 

 ABxCE-i-BCxAE— BExAC. 

 fiue 



confequenter 

 ay(^r^ -b')-i -m^r^-a-)z^x. Q. E. I. 



3. Ex problemate priori pendet fohitio fc- 

 quentis : Datis chorda arcus fimpH et radiocircuH; 

 inuenire chordas arcuum multiplorum : fiat in prio- 

 re problemate azzb fic obtinebitur chorda arcus du- 



pli 



