Problem Solving

BTGmoderatorDC wrote:

In the rectangular coordinate system above, the area of triangular region PQR is

(A) 12.5
(B) 14
(C) 10√2
(D) 16
(E) 25
Source: GMAT Prep

\[? = {S_{{\text{rectangle}}}} - \left( {{S_1} + {S_2} + {S_3}} \right)\]
\[\left. \begin{gathered}
{S_{{\text{rectangle}}}}\,\, = \,\,7 \cdot 4\,\, = \,\,28\,\,\, \hfill \\
{S_1}\,\, = \,\,\frac{{4 \cdot 3}}{2}\,\, = \,\,6 \hfill \\
{S_2}\,\, = \,\,\frac{{3 \cdot 4}}{2}\,\, = \,\,6 \hfill \\
{S_3}\,\, = \,\,\frac{{7 \cdot 1}}{2}\,\, = \,\,3.5 \hfill \\
\end{gathered} \right\}\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,?\,\,\, = \,\,\,12.5\]


We follow the notations and rationale taught in the GMATH method.

Regards,
Fabio.