Question

df and gi are parallel lines. which angles are vertical angles? ∠dec and ∠ghe ∠dec and ∠deh ∠dec and ∠fec ∠dec and ∠feh

Explanation:

Step1: Recall vertical - angle definition

Vertical angles are formed when two lines intersect. They are opposite each other and are congruent.

Step2: Analyze each option

• $\angle DEC$ and $\angle GHE$ are not vertical angles as they are not formed by the intersection of the same two - line pair.
• $\angle DEC$ and $\angle DEH$ are adjacent angles (they share a common side and a common vertex).
• $\angle DEC$ and $\angle FEC$ are adjacent angles.
• $\angle DEC$ and $\angle FEH$ are vertical angles because they are formed by the intersection of lines $DF$ and $CJ$ and are opposite each other.

Answer:

$\angle DEC$ and $\angle FEH$