Answer:
[tex]let \: the \: length \: of \: one \: side \: be \: l \\ {l}^{2} = {14}^{2} - {l}^{2} \\ 2 {l}^{2} = {14}^{2} \\ l\sqrt{2} = 14 \\ l = \frac{14}{ \sqrt{2} } \: cm \\ area = \: l \times l \\ = ( { \frac{14}{ \sqrt{2} }) }^{2} \\ = 98 \: {cm}^{2} [/tex]
