Question

what does the following notation describe? $overline{ab}perpoverline{dc}$ two parallel segments two perpendicular segments two perpendicular lines

Explanation:

In geometry, the symbol $\perp$ represents perpendicularity. The notation $\overline{AB}\perp\overline{DC}$ indicates that line - segment $\overline{AB}$ is perpendicular to line - segment $\overline{DC}$.

Answer:

two perpendicular segments