One way to find CFD is to use the fact that CFD and CFB and BFA add 180 degrees because they are supplementary angles
Another way to find CFD is to use the fact that it is congruent with angle AFE
First we have to find x:
(7x + 4) + (8x + 6) + (6x + 2) = 180 ==> 7x + 8x + 6x + 4 + 6 + 2 = 180 = 21x + 12 = 180 ==> 21x = 180-12 = 168
x = 168/21 = 8 ==> x = 8
If we use the first option to find CFD:
AFB + BFC + CFD = 180 ==> (8x + 6) + (6x + 2) + CFD = 180 ==> (8*8 +6) + (6*8 + 2) + CFD = 180
64+6+48+2+CFD = 180 ==> 70+50+CFD = 180 ==> CFD = 180 - 70 -50 = 60
CFD = 60
