Sector Subdivisions and a Square Equal to a Curved Figure
Faded quadrature geometry: equal remainders from equal sectors, and a square equated with a curved area
A faded sheet of quadrature geometry. In one figure (labelled c, d, a, b) a subdivided circular sector is treated by subtraction: taking a from a b c leaves b c, and taking a from a d c leaves d e, so that d e equals b c. A companion figure (b, a, c, d) asserts that the square a b is worth the curved area b c — the equating of a rectilinear square with a curved figure. A block of text in the left column and further faint sketches at the top are largely illegible and not transcribed.
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Equal remainders from subtracting equal sectors (a, b, c, d)
In the sector c d a b, removing a from a b c leaves b c, and removing a from a d c leaves d e; the two remainders b c and d e are therefore equal.
A square equal to a curved figure (b a, c d)
In the analogous figure the square a b is declared worth the curved b c, equating a rectilinear square area with a curved one in the manner of Leonardo's squaring of curved figures.