Question

Calcular a área do trapézio cujos vértices são A(0,0), B(7,1), C(6,5) e D (-8,3).

Answer 1

$A= \frac{1}{2} \left|\begin{array}{cccc}0&7&6&-8\\0&1&5&3\end{array}\right| \\ \\ A= \frac{1}{2} |0.1+7.5+6.3-0.7-1.6-5(-8)| \\ \\ A= \frac{1}{2} |0+35+18-0-6+40| \\ \\ A= \frac{1}{2} |87| \\ \\ A= \frac{87}{2}$