To find side $ a $ use formula:
$$ A = \dfrac{ 3 \sqrt{ 3 } \cdot a^2 }{ 2 }$$After substituting $ A = \frac{ 15177 }{ 50 } $ we have:
$$ \frac{ 15177 }{ 50 } = \dfrac{ 3 \sqrt{ 3 } \cdot a^2 }{ 2 }$$ $$ \frac{ 15177 }{ 50 } \cdot 2 = 3 \sqrt{ 3 } \cdot a^2 $$ $$ \frac{ 15177 }{ 25 } = 3 \sqrt{ 3 } \cdot a^2 $$ $$ a^2 = \dfrac{ \frac{ 15177 }{ 25 } }{ 3 \sqrt{ 3 } } $$ $$ a^2 = \frac{ 5059 \sqrt{ 3}}{ 75 } $$ $$ a = \sqrt{ \frac{ 5059 \sqrt{ 3}}{ 75 } } $$$$ a \approx 10.8089 $$