Understand Angle Transformation Properties Practice Test

On a coordinate plane, $\angle ABC$ measures $90^\circ$. The angle is rotated $180^\circ$ about point $B$ to form $\angle A'B'C'$. What is $m\angle A'B'C'$?

$\angle STU = 45^\circ$ is translated 10 units left to form $\angle S'T'U'$. How does the measure of $\angle S'T'U'$ compare to the measure of $\angle STU$?