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)
