Answer
(a) $\overline{AG}$ and $\overline{BC}$ are skew line segments.
(b) $\overline{AG}$ and $\overline{BC}$ are not congruent line segments.
(c) $\overline{GF}$ and $\overline{DC}$ are parallel.
Work Step by Step
(a) $\overline{AG}$ and $\overline{BC}$ are not parallel and they do not intersect. Therefore $\overline{AG}$ and $\overline{BC}$ are skew line segments.
(b) $\overline{BC}$ appears to be longer than $\overline{AG}$. That is, $\overline{AG}$ and $\overline{BC}$ do not have the same length. Therefore $\overline{AG}$ and $\overline{BC}$ are not congruent line segments.
(c) $\overline{GF}$ and $\overline{AB}$ are on opposite sides of a rectangle. Therefore $\overline{GF}$ and $\overline{AB}$ are parallel.
$\overline{AB}$ and $\overline{DC}$ are on opposite sides of a rectangle. Therefore $\overline{AB}$ and $\overline{DC}$ are parallel.
Therefore, $\overline{GF}$ and $\overline{DC}$ are parallel.
