Since you are asking to solve for $z$, I will proceed based on the information from the image. We have two angles that are vertically opposite in the diagram: one is $z^\circ$ and the other is labeled $70^\circ$.

Using the property of vertically opposite angles (which states that they are equal), we can set up the equation:

$z = 70^\circ$

Thus, the value of $z$ is: $z = 70^\circ$

Would you like more details or have any further questions on this?

Related Questions:

1. Why are vertically opposite angles always equal?
2. How can you use vertically opposite angles in proofs?
3. What happens when the lines are not straight but curved? Do these rules still apply?
4. What other angle relationships can we find when two lines intersect?
5. How do we calculate angles in more complex geometric figures like polygons?

Tip: Remember, in geometry, understanding properties like vertically opposite angles helps simplify many problems involving intersecting lines!