9514 1404 393
Answer:
55°
Step-by-step explanation:
A couple of auxiliary lines can be helpful.
We see that 45° is an exterior angle to the bottom triangle, which has remote interior angles that must total 45°. This means the interior angle at bottom left must be 45° -15° = 30°.
The upper right interior angle is alternate to that, so is the same measure. The exterior angle x to the upper triangle is then the sum of the remote interior angles:
x = 25° +30°
x = 55°
