Answer: 50°
Explanation:
Since angle 3 is in a right triangle we can assume one angle is 90° and then the other missing angle will be 40°
Because you take 180°-140°(the angle next to it) which will equal 40°
Now every triangle must add up to 180°
so lets take the angles we have now
90° +40°=130°
now take that 130°
180°-130°=50°
Now check your work
90°+40°+50°=180°
Angle 3 is 50°