Question

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

Explanation:

Step1: Analyze the notation

The notation $\overleftrightarrow{AB}\perp\overleftrightarrow{DC}$ uses the symbol $\perp$ which represents perpendicularity. The double - arrow notation $\overleftrightarrow{AB}$ and $\overleftrightarrow{DC}$ indicates lines (not segments, since segments would be $\overline{AB}$ and $\overline{DC}$).

Step2: Check the options

• "Two perpendicular segments" is incorrect because of the line notation ($\overleftrightarrow{}$).
• "Two congruent lines" is incorrect because the $\perp$ symbol does not denote congruence.
• "Two perpendicular lines" is correct as $\perp$ means perpendicular and $\overleftrightarrow{}$ denotes lines.

Answer:

two perpendicular lines