Answer
$5$
Work Step by Step
We know that for a matrix
\[
\left[\begin{array}{rrr}
a & b & c \\
d &e & f \\
g &h & i \\
\end{array} \right]
\]
the determinant, $D=a(ei-fh)-b(di-fg)+c(dh-eg).$
Hence here by plugging in the values: $D=0.5(2(2-5)-5(3-5)+6(3-2))=0.5(-6+10+6)=5$
$|5|=5$, thus the area is $5$.
