So angle 4 = 90- angle 5 = 90-50 = 40.

Because angle 6+ angle 1 = 90.

So the angle 1 = 90- angle 6 = 90-45 = 45.

Because the angle 1+ angle2 =180.

So the angle 2 = 180- angle 1 = 45 = 135.

Because angle 2+ angle 3 = 180.

So angle 3 = 180- angle 2 = 180- 135 = 45.

I have done this problem, and that's how I did it. Copy it intact. One hundred percent correct