[tex]d=4 \:cm[/tex]
[tex]d = l \sqrt{2} [/tex]
[tex]4 = l \sqrt{2} [/tex]
[tex]l = \frac{4}{ \sqrt{2} } [/tex]
[tex]l = \frac{4 \sqrt{2} }{2} [/tex]
[tex]l = 2 \sqrt{2}\: cm [/tex]
[tex]A = 6 {l}^{2} [/tex]
[tex]A = 6 \times {(2 \sqrt{2} )}^{2} [/tex]
[tex]A = 6 \times 8[/tex]
[tex]A = 48 \: {cm}^{2} [/tex]
