What is the measure of angle B?

Answer:
b = 60
Step-by-step explanation:
The sum of the angles of a triangle are 180
80+40+b = 180
Combine like terms
120+b =180
Subtract 120 from each side
b = 180-120
b = 60
Answer:
60°
Step-by-step explanation:
Recall that all triangles have an interior angle sum of 180. In other words:
[tex]\angle A+\angle B +\angle C = 180[/tex]
Plug in the angle values we know:
[tex](80)+(40)+\angle B = 180\\120+\angle B =180\\\angle B = 60\textdegree[/tex]