Answer for Angle B = b) 145 degrees
We know interior angles in a Pentagon sum to 540 degrees.
We can add all 5 angles and expressions to sum 540.
148 + 3x + 10 + x + 112 + 90 = 540
Combine like terms
4x + 360 = 540
Subtract 360 from both sides to isolate x
4x + 360 - 360 = 540 - 360
Simplify
4x = 180
Divide both sides by 4 to solve for x
4/4 x = 180/4
x = 45
Now find angle B = 3x + 10
Substitute value of x = 45 into expression
B = 3 * 45 + 10
B = 135 + 10
B = 145