If A = (-5,4), B = (0,3), F = (-2,1), find the area of triangle ABF.
Use the shoelace formula.
\(\text{Area} = \dfrac12 \left|\det\begin{bmatrix}1&-5&4\\1&0&3\\1&-2&1\end{bmatrix}\right| = 6\text{ sq. units}\)
+9519 
