Page:First six books of the elements of Euclid 1847 Byrne.djvu/85

BOOK II.

DEFINITION I.

RECTANGLE or a right angled parallelogram is ſaid to be contained by any two of its adjacent or conterminous ſides.

Thus : the right angled parallelogram is ſaid to be contained by the ſides and or it may be briefly defignated by

If the adjacent fides are equal; i. e. =

then

• ——— Which is the exprefſion

for the retangle under n=_=_ and

is a ſquare, and

_——_ OI —

is equal to [

—s — O