Right angles, part and whole, and a lettered triangle
Geometric axioms illustrated with circles and a triangle
The reverse continues the axiomatic notes, again in two columns: it records that all right angles are equal and repeatedly weighs the paradox that 'the part would be equal to the whole', which is offered and rejected. A lettered triangle m-n-a is used to show that a segment (a n) is only a part of the whole (a m), and a further block invokes the postulate of drawing a line at will and the definition of the circle. The diagrams are three small circles with diameters and a triangle; the sheet carries additional faint writing not transcribed.
On this page
All right angles are equal; the part cannot equal the whole
The note states that all right angles are equal and that, in the case considered, 'the part would be equal to the whole'. The claim is set out as an impossibility used to test the figures rather than an accepted result.
Triangle m-n-a: a segment as part of the whole
Beside a lettered triangle Leonardo writes 'm - n - a' and remarks that 'here a n is part of a m'. The figure makes concrete the distinction between a portion of a line and the whole line.