Apparatus
1 rectam A  rectum S
2 trianguli A   om. S
3 ad rectos basi A  ad rectos basi trianguli S
4 secetur A  sectus S
5 rectam A  rectum S
6 axem A  axim S
7 recta A   om. S
8 Quare, per 18am eiusdem, circulus bg erit () rectus ad triangulum abg A   erecta S
9 ad rectos A  ad rectos angulos S