Definition:Euclid's Definitions - Book X (III)/1 - First Apotome

Definition

 *  Given a rational straight line and an apotome, if the square on the whole be greater than the square on the annex by the square on a straight line commensurable in length with the whole, and the whole be commensurable in length with the rational straight line set out, let the apotome be called a first apotome.