Question

If m<1=140, what is m<3?

Answer 1

Angle 1 = 90 + Angle 3

Exterior angle = sum of opposite interior angles in a triangle.

Angle 1 = 90 + Angle 3

140 = 90 + Angle 3

Angle 3 = 140 - 90 = 50

Angle 3 = 50

Answer 2

50 is the correct answer When you have an external angle the two interior angle on the opposite side of the triangle add up to the external angle.
So 140 = 90 + x
50 =x is correct