Question

if m∠uxr = 80°, then what is m∠sxt?

Explanation:

Step1: Identify vertical - angle relationship

Vertical angles are equal. $\angle UXR$ and $\angle SXT$ are vertical angles.

Step2: Apply vertical - angle property

Since vertical angles are congruent, if $m\angle UXR = 80^{\circ}$, then $m\angle SXT=m\angle UXR$.

Answer:

$80^{\circ}$