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...is determined The Latin text begins with "natur," likely the end of "determinatur" (is determined) or "ponatur" (let it be placed) from the previous page. by a straight line straight line linea recta drawn from the center of the second circle, establishing a circle that intersects the first. Above that, in one place on the outside, let a straight line be drawn from the center of this third circle to the end original: "caput," literally "head." of the line proceeding from the center of the second circle, as is clear in the following figure.

[A geometrical diagram consisting of three intersecting circles. Within the overlapping areas, a square is formed by four lines connecting the centers and intersection points. The diagram is labeled with letters: G, N9, A, B, F, D, C, H. There are also smaller manuscript marks and numbers within the square: a P with a circumflex, a 3 with a circumflex, an A over N, and a 4 followed by an A. The phrase "first circle" original: "primus circulus" is written along the arc of the rightmost circle.]

Then, let the leg of the compass compass circinus (without being adjusted) be placed at the end of the aforementioned line proceeding from the center of the second circle toward the circumference circumference circunferentia. Moreover, let the other leg be placed in the center of the third circle and let it be drawn to the center of the second, establishing a circle that intersects the third and second circles each in one place, and passing through them, as appears more fully in the figure. Therefore, the four straight lines contained in the aforementioned circles constitute an equilateral square equilateral square quadratum equilaterum; for they are all equal to one another in turn. This is because any two lines in the same circle drawn from the center to the circumference These are the radii of the circles. are equal. And note that for this reason—