Question

what does the following notation describe?
ab ⊥ dc
two parallel segments
two perpendicular lines
two perpendicular segments

Explanation:

Step1: Analyze the notation

The notation $\overline{AB}$ and $\overline{DC}$ represents line segments.

Step2: Analyze the symbol

The symbol $\perp$ means perpendicular.
So, $\overline{AB}\perp\overline{DC}$ describes two perpendicular segments.

Answer:

two perpendicular segments