To find area $ A $ use formula:
$$ A = \dfrac{ d_1 \cdot d_2 }{ 2 } $$After substituting $ d_1 = \frac{ 156 }{ 5 } $ and $ d_2 = 13 $ we have:
$$ A = \dfrac{ \frac{ 156 }{ 5 } \cdot 13 }{ 2 }$$$$ A = \dfrac{ \frac{ 2028 }{ 5 } }{ 2 } $$$$ A = \frac{ 1014 }{ 5 } $$