The exterior angles of an octagon are 2x degrees,half x degrees,(x+40 degrees),110 degrees,135 degrees,160 degrees,(2x+10 degrees) and 185 degrees.find the value of x?

2 answers

all the exterior angles add up to 360°, so add up all those expressions and solve for x.
2x + x/2 + ... + 185 = 360
.... but the 4 constant angles given already add up to 590°
which means that the value of x must be negative.
i.e. x = -50.9°

The octagon must be concave.
It just said to find x, so ok then.