To find area $ A $ use formula:
$$ A = \frac{ (a + b) \cdot h}{ 2 }$$After substituting $ a = 12 $ , $ b = \frac{ 18 }{ 5 } $ and $ h = 6 $ we have:
$$ A = \frac{ (12 + \frac{ 18 }{ 5 }) \cdot 6}{ 2 }$$$$ A = \frac{ \frac{ 78 }{ 5 } \cdot 6}{ 2 }$$$$ A = \frac{ \frac{ 468 }{ 5 } }{ 2 }$$ $$ A = \frac{ 234 }{ 5 } $$