2 circles in quadruple [ratio]. The whole of the smaller equals the quarter of the larger. It follows that half of the smaller equals 1/4 of the larger. [A special sign, perhaps meaning 'semi', precedes 'circuli'.]

a, g, b, e, f, g, h, d, c

Here the sector a b c d e f equals the semicircle f g h. Take f away from the one part and the other, and the remainders are equal. Now the portion of the quarter of the larger equals the 4 portions of the whole smaller circle. Therefore the 2 portions of the semicircle are equal to the half-portion of the eighth of the larger circle, which are placed at c d. Now I take h away from the semicircle, and c from the eighth-circle, and they remain equal. And the crescent b e d, of equal curvature, are equal in length and in substance. Then I give h back to the semicircle, and c to the eighth-circle, and I add to the rectilinear a the rectilinear pyramid b, which equals c, h and d, and is squared.

p, n, o, m

I want to know what difference there is between the portion p and the portion o. And to see it better, I am certain that p and n joined together are equal to the rectilinear m. So I will take the part p from the crescent and make it o, less curved, and I will see whether the rectilinear triangle n o equals m, as the crescent p n did. And if n o is less than m, whatever m exceeds n o measures the difference that p has over o. So I cover with o a part of p, and whatever of p shows outside the o remains squared in the rectilinear difference that m has over n o.