Page:First six books of the elements of Euclid 1847 Byrne.djvu/73

RIANGLES ( and ) on equal bases and between the same parallels are equal.

Draw ||	$\scriptstyle {\left.{\begin{matrix}\ \\\\\ \ \end{matrix}}\right\}\,}$ (pr. 31.).
and ||

= (pr. 36.);

but = twice (pr. 34.),

and = twice (pr. 34.),

∴ = (ax. 7.).

Q. E. D.