To construct an angle of `60^(@)` at the initial point of a given ray.

Explanation

Steps of construction :
1. Draw a ray AB of some length.
2. Taking A as initial point draw an arc with A as centre taking any radius which intersects AB at point D.
3. Taking D as centre and with the same radius as before draw an arc which intersect the previous arc at E.
4. Draw the ray AC passing through E. `angleCAB` is the required angle.