H
E
E
L
E
M
E
N
T
S
let the points D, E have been taken at random
and
let DE have been joined,
Out of three straight lines which are equal to CD, CE, DE,
let the triangle AFG have been constructed
such that
AF is equal to CD,
AG is equal to CE,
and further
FG is equal to DE. [I.22]
