What is the measure of angle b?

Step-by-step explanation:

We know: The sum of measures of angles in a triangle is equal to 180°.

Therefore we have the equation:

b° + 80° + 40° = 180°     combine like terms

b° + 120° = 180°           subtract 120° from both sides

b° + 120° - 120° = 180° - 120°

b° = 60°

60 degrees

Step-by-step explanation:

all triangles have angles making 180 degrees. so 80+40=120

180-120=60

good luck!

cutie~