A Null Angle is one that measures 0 degrees, that is, that which occurs when two lines coincide, without producing a distance between in which to calculate an angle or space between them. To draw a fully described null angle, it is necessary to draw a complete line between the center and one of the sides of the circumference and to emphasize that the straight line is described as two lines, one mounted on top of the other. It is called null because it simply does not exist, its value in any denomination and unit is 0 (zero).
Its application in practice is technical, in fact, with the circumference already made with a compass or another instrument, it is enough to point out that two lines are drawn on the line equivalent to its radius and that they coincide in line and direction.
In everyday life when saying that two vehicles go along the same street at the same time, leaving a linear and parallel trail, without having an angle because they go on only one road.
Mathematically, an angle 0 times a radian. To represent a null angle, just draw a circle and denote that the union of the center with one of the sides of the circle is a null angle as well. It can be done with a compass or with a protractor, a straight ruler should also be used. So that it is not confused with a complete angle, the correct nomenclature must be used, indicating the presence of two lines instead of one.
