Bisecting an Angle
To bisect an angle means to divide it in half. If you know the size of the angle, you can bisect it by simply dividing the size by 2 and laying off the result with a protractor.
Geometric construction for bisecting an angle is shown in figure 4-11, To bisect the angle AOB,
first lay off equal intervals from O on OA and OB. With the ends of these intervals as centers,
strike intersecting arcs of equal radius at P. Draw a line from O through the point of intersection of the arcs, P. The line OP bisects angle AOB.
(Source: NAVEDTRA 14069, U.S. Navy)