Answer:
B = 70
Step-by-step explanation:
The sum of the angles of a triangle add to 180 degrees
A + B + C = 180
40 + 2x-30 + x+20 = 180
Combine like terms
3x + 30 = 180
Subtract 30 from each side
3x+30-30 = 180-30
3x = 150
Divide by 3
3x/3 =150/3
x = 50
We want to find angle B
B = 2x-30
=2(50) - 30
= 100 - 30
= 70
