I tried to answer this one and got it wrong the question is “find the measure of each angle indicates”

∠F = 80

Step-by-step explanation:

Let's find inner ∠D first, as you can see, it's a straight line but a line is in between, the outer angle is 120, and a straight line is 180, so 180 - 120 = 60. The inner ∠D is 60, now we can find ∠F, a triangle is 180:

40 + 60 + ∠F = 180

100 +∠D = 180

subtract 100 from both sides

∠F = 80

the answer is b