Vertical angles are two non-adjacent angles formed by intersecting two lines. The intersection forms two pair of vertical angles. And it is true that:
[tex]\begin{gathered} x=40 \\ y=z \end{gathered}[/tex]
For the green triangle, we can use the triangle sum theorem, which states that the sum of the internal angles of a triangle is equal to 180, so:
[tex]\begin{gathered} x+y+35=180 \\ 40+y+35=180 \\ \text{solve for y:} \\ y+75=180 \\ y=180-75 \\ y=105 \end{gathered}[/tex]
Using the same theorem for the blue triangle:
[tex]\begin{gathered} w+105+49=180 \\ w+154=180 \\ w+154=180 \\ \text{solve for w:} \\ w=180-154 \\ w=26 \end{gathered}[/tex]
? = w, therefore, ? = 26
