Help me please don't understand (see picture)

< F would be 140 degrees

Step-by-step explanation:

So what you would do is that since they told you angle D is 40 degrees and you know that the 2 lines in there are parallel, and since they are asking for angle F, whne you add angle F and angle H they should equal 180 degrees which you know so you just subtract 40 degrees from 180 and you  get 140 degrees which if angle F and you can subtract 40 since angle H and angle D would be congruent.

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.

its totaly b

your welcome btw