Ratio Tables Serving Algebra (Sets 201 and 212)
Paired magnitudes and their rearrangement, with a note that Euclid's propositions serve algebra
Two numbered ratio-sets, 201 and 212, list paired magnitudes: a 12 to c 16, b 6 to d 8, e 3 to f 4, and then a rearranged set a 16 to f 12, b 8 to c 6, e 4 to d 3. A heading remarks that the fourth and fifth propositions of the second book serve for algebra (l'arcibra). The sheet carries the matching line-segment diagrams ruled across the page.
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Ratio-sets 201 and 212
Set 201 pairs a 12 with c 16, b 6 with d 8, and e 3 with f 4; set 212 rearranges the same family as a 16 with f 12, b 8 with c 6, and e 4 with d 3. The two tables show one proportional series and its permutation.
Euclid's propositions put to algebra
A heading notes that the fourth and fifth propositions of the second book serve for algebra (fa per l'arcibra). The remark links the geometric proportion theory of the tables to algebraic calculation.