Corollary of the fourth: square split into two rectangles
A square of 144 divided into rectangles, with workings headed Second and Third
Headed as the corollary of the fourth proposition, the sheet decomposes the square just as on the recto and divides a line at the points a, c, b. A square of side 12 and area 144 is cut into two rectangles, and columns of figures are worked beneath under the headings Second and Third. The numbers (96, 84, 64, 48, 32, 33, 16) carry the same division through in calculation.
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Square of 144 divided into two rectangles
The square of side 12 and area 144 is split into two rectangles across the divided line a, c, b. The figure repeats the decomposition of the recto as a corollary to the fourth proposition.
Workings headed Second and Third
Beneath the square two columns of figures are worked under the headings Second and Third, among them 96, 84, 64, 48, 32, 33 and 16, all summing toward 144. They carry the geometric division through as arithmetic.
Square decomposed as on the recto
A square is broken up in the same manner as the figure on the recto folio, tying this corollary to the preceding fourth proposition. The repeated decomposition sets up the two-rectangle division below.