2o gali trianguli ſunc æquales duobus

rectis. 1

IV. Triaugala 2quilatera ſunt aqui⸗ angulas& vice versâ: Triangula aqui- anguls ſunt aquilatera.

V. Quauab dus angeli dworum trian-

Sularum æquales ſunt, omer trer anguli bujus triangul omnibua tribas augulu al= terius trianguli eruvs ⸗qualese..

IV. Majus trianguli latu, majoren fubttndis angulam„& major angulas 2 majori latere ſubtenditur. Nota: ſub- tendi, i. e. opponi.

VII. Ouuitrianguli duo latera,quomo* modocung; ſumta, tertib ſunt majora,

VIII. Triangala ahuianguls Habent læteræ circa æsuales angulos proportio- nabia. Vid Clavium ad prop. IV. jib,, 5. Eueclidis., 1

CAb. V. a e Quadrangblis. I. Detinitiones. 1,'Ulagrangulum eſt ſigura, quæ comprehendicur quatuor lineis rectis

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