Footnote 76
Supp. Prop., §43a.  The reading versam (as in the MS.) is absurd.  We must also read `nat come', as, if the base were approachable, no such trouble need be taken; see Art. 41.  In fact, the present article is a mere repetition of Art. 43, with different numbers, and with a slight difference in the method of expressing the result.  In fig. 18, if b'c' = 3, bc = 4, we have E'B = 3/12 BC, EB = 4/12 BC; or, subtracting, EE' = 4-3/12 BC; or BC = 12 EE'.  Then add the height of E, viz. Ea, which = AB.