9514 1404 393
Answer:
132°
Step-by-step explanation:
Name the vertex of each angle the same as the angle letter. Name the intersection of the "horizontal" and "vertical lines" point Q.
Angle ZXQ is vertical to ∠x, so is the same measure.
Angle YQX is the value that makes the sum of angles in triangle XYQ be 180°. That is ...
∠YQX = 180° -51° -57° = 72°
This is also the measure of its vertical angle in the other triangle. Angle z is the sum of that vertical angle and 60°, so we have ...
∠z = 72° +60°
∠z = 132°
_____
<em>Additional comment</em>
The relations we used are ...
- vertical angles are congruent
- sum of angles in a triangle is 180°
- an exterior angle is equal to the sum of the remote interior angles
denotes the set of elements in both A and C, which is
.
denotes the complement of set B, which is the set of all elements that are in the universal set that are not in set B. In this case, this set is