Squaring circular sectors and figures
Constructions that turn sectors and similar figures into equal rectilinear squares
A dense sheet of geometric studies dominated by circular sectors, a twelve-pointed star inscribed in a circle, and squares crossed by their diagonals. The notes argue that two rectilinear triangles a q g and b q f are equal to the circular sector a b q, so that a portion of the sector can be cut away and repositioned to build an equal rectilinear square. A short remark treats two figures a and b as similar because they arise from the numbers 8 and 4. The mirror-script marginal text was recorded in the transcription.
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Two triangles equal to a circular sector
Leonardo asserts that the two rectilinear triangles a q g and b q f together equal the circular sector a b q. By removing the portion a b d e from the sector and setting it below at g q f, he claims to construct a rectilinear square a b g f equal to the original curved figure a e b g q f.
Similar figures arising from 8 and 4
Two labelled figures a and b are said to be similar because they arise from the numbers 8 and 4. The pairing links the proportional relation of the numbers to the geometric similarity of the shapes.
Twelve-pointed star inscribed in a circle
A large twelve-pointed star polygon is drawn inside a ruled circle, its points reaching the circumference and its interior filled with hatched triangular wedges. Smaller circular figures nearby are divided by radiating chords into equal segments.