Commensurable Quantities and Their Common Measure
Line segments a, b, c, d, e with numerical workings (28, 119) on shared divisors
The note defines two "communicant" (commensurable) quantities: whatever the first shares a common measure with, the second will too, and they with one another, while whatever is not commensurable is set apart. Beside it are three line segments lettered c, b and a, with further points d and e joined by pen-strokes, and a column of figures — 4·33, 28, 7, 17, 7, 119 — worked out below. A last small division shows 3, 119 and 28 separated by a pen-stroke.
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Communicant (commensurable) quantities share a measure
Two quantities are called communicant: whatever the first has a common measure with, the second will have too, and they with one another; whatever it is not commensurable with is excluded.
Segments c, b, a with points d, e
Three line segments are lettered c, b and a, with the further labels d and e placed below segment c, the segments linked by curved pen-strokes to illustrate the shared measure.
Numerical reduction (28, 119)
A short division worked in ordinary (non-mirror) script sets 3 against 119 and 28, part of the column of figures 4·33, 28, 7, 17, 7 and 119 accompanying the segments.