Question

the measure of ∠xoh can be calculated. m∠xoh = 80 ° reason:

Explanation:

Step1: Identify vertical angles

Vertical angles are equal.

Step2: Determine the relationship

$\angle ROX$ and $\angle XOH$ are vertical angles.
Since $m\angle ROX = 80^{\circ}$, then $m\angle XOH=80^{\circ}$ (vertical angles theorem).

Answer:

Vertical angles theorem.