Mandal WA. Proof without Words: (a+b+c)^2,(a+b-c)^2,(a+b+c)^2-(a+b-c)^2. ojsm [Internet]. 2018 Feb. 17 [cited 2024 Nov. 21];78(1). Available from: https://ohiomathjournal.org/index.php/OJSM/article/view/6216