Answer: M∠2 just mean measure of angle 2,
Step-by-step explanation: So I worked it out and the awnser is B.
3 numbers/the degrees of all 3 sides always add up to 180 degrees.
Side 1 is 60 degrees and the left side is 20, so 20 + 60 + 3 (unkown number) = 180
60 - 20 = 100,
