Adjacent angles add up to 180° so angle a and the one labeled 75° add up to 180
So we do 180-75=105
a=105°
Vertical angles are congruent, so b and 75° are congruent.
so b=75°
Angles a and c are congruent, we know angle a is 105
so angle c=105°
Corresponding angles are also congruent, angles a and e are congruent
so angle e=105°
Angle 75° and d are also corresponding angles
so angle d=75°
Angles b and f are corresponding angles
so f=75°
And angles c and g are corresponding angles
so g=105°