Respuesta :

Hi.
This is just messing around with exterior angles.
I say around 120 degrees, if I forgot what exterior angles were.
But with quick calculation, it is probably 120 degrees
Sum of all exterior angles = 360°

Given that it is a regular octagon, 
one angle = 360 ÷ 8 = 45°

Given that the other is a equilateral triangle ( all angles being 60° each)
x = 45 + 180 - 60 = 165°

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Answer: x = 165°
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