Answer:
67.9
Step-by-step explanation:
The polygon has 6 sides.
Sum if interior angles = (n-2)180
=(6-2)180
= 4 x 180
= 720
A + B + C + D + E + F = 720
x+40 + 2x-9 + 2x + 2x + x + x+78 = 720
9x + 109 = 720
9x = 720-109
9x = 611
x = 611/9
x = 67.9