Page:First six books of the elements of Euclid 1847 Byrne.djvu/72

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

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

Produce .

and are parallelograms on the same base, and between the same parallels, and therefore equal. (pr. 35.)

∴ $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	= twice	$\scriptstyle {\left.{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \ \end{matrix}}\right\}\,}$ (pr. 34.)
	= twice

∴ = .

Q. E. D.