Question

which statement is true about the diagram?
∠def is a right angle.
m∠dea = m∠fec
∠bea ≅ ∠bec
eb bisects ∠aef.

Explanation:

Step1: Recall vertical - angle property

Vertical angles are equal. $\angle DEA$ and $\angle FEC$ are vertical angles.

Step2: Analyze other options

There is no indication that $\angle DEF$ is a right - angle. There is no evidence that $\angle BEA\cong\angle BEC$ or that $\overrightarrow{EB}$ bisects $\angle AEF$.

Answer:

$m\angle DEA = m\angle FEC$