what is the measure of ∠x? angles are not necessarily drawn to scale.

Explanation:

Step1: Identify the right - angle

The whole angle $\angle AOC$ is a right - angle, so $\angle AOC = 90^{\circ}$.

Step2: Use angle - addition property

We know that $\angle AOB+\angle BOC=\angle AOC$. Given $\angle AOB = 73^{\circ}$ and $\angle BOC=x^{\circ}$, then $x + 73=90$.

Step3: Solve for $x$

Subtract 73 from both sides of the equation: $x=90 - 73$. $x = 17$

Answer:

$17$