hi emakarov, sorry i don't think i explained very well,

first off i meant (1/3) * √3 which i think is the same as what you wrote 1 / √3

secondly i what i was trying to say was that both these values

sinθ = -1/2 = -1/6pi and

tanθ = 1/√3 = 1/6pi

but this is where i get stuck, because i have two values which are either positive or negative of 1/6 pi and which are neither in the third quadrant so i thought it must be -5/6pi (-150 degrees)

but this is where i need help