Explanation:
∠, the
angle symbol
In geometry,
an angle is the figure formed by two rays sharing
a common endpoint, called the vertex of the
angle. The magnitude of the angle is the "amount of rotation"
that separates the two rays, and can be measured by considering the length of
circular arc swept out when one ray is rotated about the vertex to coincide
with the other.
http://en.wikipedia.org/wiki/Angle
Angle
bisector
An angle bisector divides the angle into two
angles with equal measures. An angle only has one
bisector. Each point of an angle bisector is equidistant from the sides of the
angle.
The interior bisector of an angle is the half-line or line segment that divides an angle
of less than 180° into two equal angles. The exterior bisector is the half-line
that divides the opposite angle (of greater than 180°) into two equal angles.
To bisect an angle with straightedge
and compass, one draws a circle whose center is the vertex. The circle meets
the angle at two points: one on each leg. Using each of these points as a
center, draw two circles of the same size. The intersection of the circles (two
points) determines a line that is the angle bisector. (Our solved example in
mathguru.com uses this concept)
http://en.wikipedia.org/wiki/Bisection#Angle_bisector
The above explanation is copied from
Wikipedia, the free encyclopedia and is remixed as allowed under the Creative
Commons Attribution- ShareAlike 3.0 Unported License.