Answer:
m = 40
Explanation:
The triangle inside the circle has 2 equal sides ( the radii ) of the circle, thus
The base angles are congruent both 50°
The 3 angles on the tangent sum to 180°, so
m + 50 + 90 = 180
m + 140 = 180 ( subtract 140 from both sides )
m = 40