( ) 
vx Rhodoneas E I C, turn ellipticas F V Q, invicem se- 
quantur-, quare & perimeter femifolii Rliodonese erit 
quadrant! curvse ellipticas ^equalis, 6c duo quselibet 
folia perimetrum habebunt integrae curvas eliipfeos x- 
•qualem'. Quod erat, < 5 cc. 
COROLL ARIA. 
I. Patet, Rhodoneain effe ellipfim quandam contra- 
dam nam (i confiuentibus in centrum C pundis T, f, 
ordinatag elliptici quadrantis V T, w in ramos abeant 
a centro C didudos, quadrans ellipfis in femifolium 
Rhodoneae contrahetur, eadein curvae longitudine ma- 
nente. 
II. Hinc iterum patet, Rliodoneam elTe medietatem 
fedoris circularis circumfcripti ^ eft enim femifolium 
E I C medietas quadrantis elliptici F V Q,C, in quern 
expanderetur, ft rami ab eorum centro diffoluti fierent 
paralleli, 6c redae C Q,perpendicuiares ^ cumque qua- 
drans ellipfis fit ad quadrantem circularera, ut bafis 
Q^C ad bafim C A, nempe ut a ad in qua etiam ra- 
tione eft fedor E G A ad eundem quadrantem, ex Prop, 
primay patet, ejufmodi fedorem squari quadranti ellip- 
tico, ideoque duplum efie infcripti folii Rhodonese. 
III. Infuper colligitur, asquales efie foliorum perime- 
tros in Rhodoneis^, quaruin ratio fit reciproca, & radii 
fuorum circulorum in eadem reciproca ratione fibi re- 
fpondeant, nam fi radius CF, vel EC Figur^i 17. 2d- 
quaretur bafi ellipfis CQ^Figur^ 16, < 5 c viciflim radius 
C F iftius sequaret bafim C Q, ellipfis alterius F/gnr^^ 
patet, eandem ellipfim F V utrobique refultare debere, 
quippe iifdem femiaxibus defcriptam, eamque fore u- 
trivis folio ifoperimetram, exiftente ibi ratione ad 
hie 
