Answer:
19 degrees.
Step-by-step explanation:
First solve the angles in the top triangle:
FHG = 180 - 135 = 45 (angles on a straight line = 180)
FGH = 180 - 105 = 75 (angles on a straight line = 180)
Using these we get HFG = 180 - 45 - 75 = 60 (angles in a triangle = 180)
Then because HFG is directly opposite DFC on the crossed lines, we know they are equal: DFC = 60
FDC = 180 - 119 = 61 (anges on a straight line = 180)
Now if we label ABC (the target angle) as x then we known ACB = 180 - 40 - x.
With this we know FCD = 180 - ACB = 180 - (180 - 40 - x) = 40 + x (angles on a straight line).
Finally using the FDC triangle we have 40 + x + 60 + 61 = 180 so x = 180 - 40 - 60 - 61 = 19 degrees.
