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# Title: [Francisci Vietae Opera Mathematica] Francisci Vietæ Opera Mathematica (shelfmark Leibn. Marg. 101)
# Folio 230, page id 845634801:0236
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30
EFPECTLONY H AEOM E YRIC A RYM
PROPOSTETO IV.
Deleribere eriangulum rectan.
Sulum.
Reperira superiore constructione
connectatur AD. Dico Factum esse quod
oporcuic. Triangulum enim ese AFD,
ipsumque rectangulum, quoniam anou-
lus AFD est rectus, ur demonstrarur in.
Elemenris.
PROPOSFETO
Datis duabus lineisrectIS, IN VENIEC ICCIAM MHTCL Cas PTOPOTtiONaLCM.
Opus multiplicationis. Illud enim est, DatiS LAFEFIDUS IIVCHIKCPL2HIHHI, LVC
exhibere quadracum ipliplano aequale. Fradirum est aurem quod ticab ex
cremisplanum, aquale esse medix quadrato.
Sine datae duxe rectae lineae BF, F C. O-
Porret invenire mediam inter eas pro-
Porcionalem. Continuetur B F longitu-
dine F C,  B C lecerur bifariam in A:
EcC cenrro A interrallo AB vel A C de-
Scribatur circulus, e exciretur ad pun-
cum F perpendicularis, abscindens cir-
cumferenciam in D. Dico Factum esse
quod oporruit. Mediam enim quaelitam
esse D F, ur manifectum Ac ex descriprio-
ne canonica erium proportionalium.
Sic dato plano, datur quadra-
cum xequalc.
PRODOSTTTO VT.
Dacis duabus lineis rectis, inveie terriam proportionalem.
Datum planum seu plano aequale
quadratum, rectae adplicare e la-
ticudinem ortiram extribere. Qua-
dratum videlicet mediae adplicatur ad
primam, ex oriturtertia.
Sine datx duxe linea rectX B F, F D.
Oporret invenire certiam proportiona-
lem. Inclinentur ad rectos angulosBF.
F D, _ connectatur BD, quae secerur bi-
Fariam ad rectos angulos a recta AHI in-
cercipience iplam BD in G7, ip(am verO
BF in A, ECcenerO A, intervallo A B vel
A D delcribatur circulus, ad cujus cir-
cumferenciam prorrahacur B Fin C. Di-
Opusadplicationis. Illud enim est,
Ota.
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