Answer:
50
Step-by-step explanation:
The inside of a triangle equals 180 and so you subtract the other two values(100 and 30) to 180 and you get 50.
The sum of the angles of a triangle add to 180
A+B+C = 180
A + 100+ 30 = 180
A + 130= 180
Subtract 130 from each side
A+130-130= 180-130
A = 50
