Angle Bisector

**Definition of An Angle Bisector**

- Angle bisector is a ray that divides an angle into two equal parts.

**More about Angle Bisector**

- Angle bisector is also called the internal angle bisector.
- Angle bisectors of a triangle intersect at a point called incenter of the triangle.
- A line or a line segment can also be angle bisectors at times. For example, the angle bisectors of polygons are line segments.

**Examples of An Angle Bisector**

In the example shown, **OA** is the angle bisector. It divides 60° into two equal parts, (two 30°'s).

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__Solved Example on __**Angle Bisector**

In the given figure,
is the angle bisector of
and
is the angle bisector of
. If
and , then find the value of *y*.

**Choices:**

A. 56°

B. 28°

C. 20°

D. 112°

**Correct Answer: C**

**Solution:**

**Step 1:** , so
, because is an angle bisector of .

**Step 2:** implies that , because bisects .

**Step 3:** So, 3*y* - 4 = 56 gives *y* = 20°.

__Related Terms for Angle Bisector __

**Additional links for Angle Bisector**