formula mediei aritmetice
[tex] \frac{x + y}{2} \\ = > \frac{9 \sqrt{2} + y}{2} = 18 \sqrt{2} [/tex]
inmultim pe diagonala
[tex]9 \sqrt{2} + y = 2 \times 18 \sqrt{2} < = > 9 \sqrt{2} + y = 36 \sqrt{2} = > y = 36 \sqrt{2} - 9 \sqrt{2} = > y = 27 \sqrt{2} [/tex]
facem si proba(sau verificarea)
[tex] \frac{9 \sqrt{2} + 27 \sqrt{2} }{2} = 18 \sqrt{2} = > \frac{36 \sqrt{2} }{2} = 18 \sqrt{2} = > 18 \sqrt{2} = 18 \sqrt{2} \: adevarat[/tex]
