Question

tan 240 degrees, use that 180 degrees + 60 degrees =240 degrees

Answer 1

tanx = sinx/cosx -> tan(240) = sin(240)/cos(240) -> -sin(60)/-cos(60) -> sin(60)/cos(60)

This works because sin(180) = 0 then sin(180)/cos(180) = 0/-1 = 0