## Elementary Geometry for College Students (6th Edition)

(a) $\overline{AB}$ and $\overline{DC}$ are parallel. (b) $\overline{AB}$ and $\overline{FE}$ are skew line segments. (c) $\overline{AB}$ and $\overline{FE}$ are perpendicular.
(a) $\overline{AB}$ and $\overline{DC}$ are on opposite sides of a rectangle. Therefore $\overline{AB}$ and $\overline{DC}$ are parallel. (b) $\overline{AB}$ and $\overline{FE}$ are not parallel and they do not intersect. Therefore $\overline{AB}$ and $\overline{FE}$ are skew line segments. (c) $\overline{AB}$ and $\overline{GF}$ are on opposite sides of a rectangle. Therefore $\overline{AB}$ and $\overline{GF}$ are parallel. $\overline{GF}$ and $\overline{FE}$ meet at a right angle. Therefore, $\overline{GF}$ and $\overline{FE}$ are perpendicular. Therefore, $\overline{AB}$ and $\overline{FE}$ are perpendicular.