Question

Can someone explain this to me I already know the answer is 50 but how is it 50?

Answer 1

Angle 10 is 140 degrees

Angle 2 = Angle 10 = 140 degrees (Vertically Opposite Angles)

Angle 5 + Angle 4 = Angle 2 (Corresponding Angles)
Angle 5 + Angle 4 = 140
90 + Angle 4 = 140 (Angle 5 is 90 degrees because c is perpendicular to d)
Angle 4 = 50