Draw the following pairs of angles as adjacent angles. Check whether they form linear pair.

Niharika took two angles $130°$ and $50°$ and tried to check whether they form a linear pair. She made the following figure.

Can we say that these two angles do not form a linear pair? If not, what is Niharika's mistake?

Name two pairs of vertically opposite angles in the figure.

Find the measure of $x, y$ and $z$ without actually measuring them.