Euclid's Book 10 - Proposition 29

Lemma 1 : To find two square numbers such that their sum is also square.
Lemma 2 : To find two square numbers such that their sum is not square.
Proposition : To find two rational straight lines commensurable in square only such that the square on the greater is greater than the square on the less by the square on a straight line commensurable in length with the greater.
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