Question

What is the measure of angle B?​

Answer 1

60°

Explanation:

Recall that all triangles have an interior angle sum of 180. In other words:

`\angle A+\angle B +\angle C = 180`

Plug in the angle values we know:

`(80)+(40)+\angle B = 180\\120+\angle B =180\\\angle B = 60\textdegree`

Answer 2

b = 60

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