Question

COMO CALCULAR A AREA DE UM TRAINGULONO PLANO CARTESIANO

Answer 1

$\mathrm{Sendo\ A(x_A;y_A), B(x_B;y_B)\ e\ C(x_C;y_C)\ os\ v\acute{e}rtices\ do\ \triangle ABC:}\\\\ \mathrm{\acute{A}rea\ \to\ A=\dfrac{1}{2}\big|D\big|,\ sendo\ D=\left|\begin{array}{ccc}\mathrm{x_A}&\mathrm{y_A}&1\\\mathrm{x_B}&\mathrm{y_B}&1\\\mathrm{x_C}&\mathrm{y_C}&1\end{array}\right|}}$