a – d c b - m

* The lune a d is worth the semicircle it encloses. Take d away from that lune and take b c away from that semicircle, and there remains the triangle m equal to the remainder of the lune a.
The larger semicircle is worth twice the smaller. Take the smaller from the larger semicircle, and there remains the lune, the excess of the larger semicircle, equal to the smaller semicircle. And by the sixth [proposition] of this [book], which said: 'The similar parts of circles have among themselves the same proportion as their wholes,' therefore the portion d is worth twice the smaller portion c, because the semicircles are in double proportion to one another; and from this it follows that the two smaller portions b c are worth the larger portion d. And if you take the two smaller portions from the smaller semicircle and take the larger portion from the larger semicircle, there will remain a, the remainder of the larger, equal to the triangle m. If two equal things are placed one upon the other, etc.

f – e – g c – h d – b a

Here, there being 2 circles one quadruple the other, the quarter of the larger is worth the whole of the smaller.

a - b c

a is worth b, because the lune a c is an eighth of a circle; and the sector is likewise.

First - one and a quarter.

Second - a half and an eighth.

Third - a quarter and a sixteenth.
A half and a quarter.
A quarter and ...
One and a half.

d c – r – b a – h K f - m n g

a b n n is worth c d, because one circle is double the other.
f g, a half-portion of a circle, is worth the two portions c d, being one born of a portion of a circle that is quadruple the circle of c d. Take therefore c a n from the semicircle and take f g from the lune, and there remains K equal to r h. Take the smaller dotted lune and put it at a, and take the larger dotted lune and put it back where the smaller lune was taken, and thus you will have made two triangles equal in figure and in quantity.

: b; f c a - d - e; n - b - m - p
Let two portions of a circle be divided, the one ...

a

From the half-circle one removes the half by means of the second (circle), and the 2 lunes are worth that lune.

To square.

a - d - b c

a is worth b and c is worth d.

The same curvature.

7
150 19
88

150 stadia and 90 stadia.

150 square towers of 200 feet each, these walls a hundred feet high.

Suisset.