Table of the fourth proportion with quadruple ratios
Segments e–f, a–c, b–d and g–h grouped by the quadruple ratio
Headed 'Fourth', this leaf continues the sequence of proportion tables. Four rows of ruled segments pair their values e 24 / f 32, a 12 / c 16, b 3 / d 4 and g 18 / h 24, with the middle row flanked by the mark 'quadruple' (4la) on either side. The paired terms illustrate a fixed multiplex ratio between magnitudes, in faint pencil gone over in pen.
On this page
The 'fourth' and quadruple ratios
Under the heading 'Fourth' the page pairs e 24 / f 32, a 12 / c 16, b 3 / d 4 and g 18 / h 24. The central row a–c is flanked left and right by the marker 'quadruple' (4la), signalling a fourfold ratio between the compared quantities.