How large an angle is formed between a line and the [[$ x $]] axis, when the slope of the line is

a) [[$ 1 $]]?



Answer: ° angle.

b) [[$ 2 $]]?



Answer: ° angle.

c) [[$ \displaystyle\frac {2} {3} $]]?



Answer: ° angle.

d) [[$ \displaystyle\frac {1} {6} $]]?



Answer: ° angle.