H
E
E
L
E
M
E
N
T
S
as AB is to CD, so is EF to QR,
and
there have been described on AB, CD the similar and similarly situated figures KAB, LCD,
and
on EF, QR the similar and similarly situated figures MF, SR,
therefore,
as KAB is to LCD, so is MF to SR.
But also, by hypothesis,
as KAB is to LCD, so is MF to NH;
therefore also,
as MF is to SR, so is MF to NH. [V.11]
