A (straight line) commensurable in length with an apotome is an apotome, and (is) the same in order. * Let $AB$ be an apotome, and let $CD$ be commensurable in length with $AB$. * I say that $CD$ is also an apotome, and (is) the same in order1 as $AB$.
(not yet contributed)
Euclid's expression "(not) being the same in order" means that the resulting irrational number is "(not) of the same kind" as that irrational number, with which it is commensurable. ↩