Hi!
The Triangle Angle Sum Theorem states that the sum of the interior angles in all triangles will always be 180 degrees.
We can set up an equation with the given information:
40 + (2x - 30) + (x + 20) = 180
Remove parentheses:
40 + 2x - 30 + x + 20 = 180
Combine like terms:
30 + 3x = 180
Subtract 30 from both sides:
3x = 150
Divide both sides by 3:
x = 50
Now, the problem wants us to solve for angle B.
Angle B is (2x - 30) degrees. We know the value of x, so we just have to substitute:
(2x - 30)
(2(50) - 30)
100 - 30
70
Therefore, angle B is 70 degrees.
