MathNet 2015-part-01 — 191 problems (EN–VI) Question 137

In the figure below, the right trapezoids $ABCD$ and $AEFG$, with $BC \parallel EF$ and $CD \parallel FG$, have the same area. Knowing that $BC=4$, $AD=7$, $CT=1$ and $TD=2$, determine the length of the segment $DG$.