To find side $ a $ use formula:
$$ d_1^2 + d_2^2 = 4 \cdot a^2 $$After substituting $ d_1 = 182 $ and $ d_2 = 131 $ we have:
$$ 182^2 + 131^2 = 4 \cdot a^2 $$ $$ 33124 + 17161 = 4 \cdot a^2 $$ $$ 4 \cdot a^2 = 50285 $$ $$ a^2 = \frac{ 50285 }{ 4 } $$ $$ a^2 = \frac{ 50285 }{ 4 } $$ $$ a = \sqrt{ \frac{ 50285 }{ 4 } } $$$$ a = \frac{\sqrt{ 50285 }}{ 2 } $$