Page:First six books of the elements of Euclid 1847 Byrne.djvu/71

Rh ARALLELOGRAMS ( and ) on equal bases, and between the same parallels, are equal.



Draw and ,

= =, by (pr. 34, and hyp.);

∴ = and || ;

∴ = and ||  (pr. 33.)

And therefore is a parallelogram:

but =  =  (pr. 35.)

∴ =  (ax. 1.). Q. E. D.