We know that
[tex]m\angle3=56[/tex]If angle 2 and angle 3 are complementary, then by its definition we can express the following.-
[tex]\begin{gathered} m\angle2+m\angle3=90 \\ m\angle2=90-m\angle3 \\ m\angle2=90-56=34 \end{gathered}[/tex]Then, angle 1 and angle 2 are equal by definition of vertical angles.
[tex]m\angle1=m\angle2=34[/tex]