The value of a whole is equal to the sum of its parts, so thus:
Interior angle measure = angle 1 + angle 2 + angle 3 .... + angle n
A hexagon has a total interior angle measure of 720° and we know the measure of all the other angles so insert into the above equation:
[tex]720=110+130+120+(x-20)+(x-60)+(x-40)\\\\720=360+3x-120\\\\720+120-360=3x\\\\3x=480\\\\x=160[/tex]
Angle F = (x - 20)
F = 160 - 20
F = 140°
