If a parallelogram, falling short^{1} by a square figure, is applied to some straight line then the applied (parallelogram) is equal (in area) to the (rectangle contained) by the pieces of the straight line created via the application (of the parallelogram).
(not yet contributed)
Proofs: 1
Proofs: 1
Note that this lemma only applies to rectangular parallelograms (translator's note). ↩