**ray in the interior of an angle forming two congruent angles**.

What is internal aspects of ethnic identity?

**what is ethnic identity in anthropology**.

### Contents

What most textbooks call the Angle Bisector Theorem is this: An angle bisector in a triangle divides the opposite side into two segments which are in the same proportion as the other two sides of the triangle. In the figure above, ¯PL bisects ∠RPQ , so **RLLQ=PRPQ .**

The internal (external) bisector of an angle of a triangle **divides the opposite side internally (externally) in the ratio of the corresponding sides containing the angle**.

Exterior angle bisector theorem : The external bisector of **an angle of a triangle divides the opposite side externally in the ratio of the sides containing the angle**.

The exterior bisector of an Angle is **the Line or Line Segment which cuts it into two equal Angles on the opposite “side” as the Angle**. For a Triangle, the exterior angle bisector bisects the Supplementary Angle at a given Vertex. It also divides the opposite side externally in the ratio of adjacent sides.

What is the Exterior Angle Property? An exterior angle of a triangle **is equal to the sum of its two opposite non-adjacent interior angles**. The sum of the exterior angle and the adjacent interior angle that is not opposite is equal to 180º.

Definition of bisector : one that bisects especially : **a straight line that bisects an angle or a line segment**.

The angle bisector theorem is commonly used when the angle bisectors and side lengths are known. It can be used in a calculation or in a proof. An immediate consequence of the theorem is that **the angle bisector of the vertex angle of an isosceles triangle will also bisect the opposite side**.

It is a **theorem in Euclidean geometry that the three interior angle bisectors of a triangle meet in a single point**. … The incenter lies at equal distances from the three line segments forming the sides of the triangle, and also from the three lines containing those segments.

Bisectors are **very important in identifying corresponding parts of similar triangles** and in solving proofs. In a triangle if you draw in one of your angle bisectors, remember there’s three, one for each vertex, you’re going to divide the opposite side proportionally.

Properties. The interior angles of a **triangle always add up to 180°** Because the interior angles always add to 180°, every angle must be less than 180° The bisectors of the three interior angles meet at a point, called the incenter, which is the center of the incircle of the triangle.

The measure of an exterior angle of a triangle is equal to the sum of the measures of the two non-adjacent interior angles of the triangle. **m∠4=m∠1+m∠2**. Proof: Given: ΔPQR.

In the below figure line PQ is the bisector of AB. Example of **Line Segment Bisector**: Consider a line AB = 4cm. A line segment bisector will cut it into two equal parts of 2cm each. If a bisector cuts the line segment into two equal parts at 90o, then the bisector is known as perpendicular bisector.

**A line that splits an angle into two equal angles**. (“Bisect” means to divide into two equal parts.)

Angle bisector. The angle bisector of an angle of a triangle is **a straight line that divides the angle into two congruent angles**. The three angle bisectors of the angles of a triangle meet in a single point, called the incenter .

The perpendicular bisector theorem states that **if a point is on the perpendicular bisector of a segment, then it is equidistant from the segment’s endpoints**. In other words, if we hanged laundry lines from any floor of our tower, each floor would use the same length of laundry line to reach the ground.

Any point on the perpendicular bisector of a segment is equidistant from the endpoints of the segment. … Since OA=OB=OC , point O is equidistant from A , B and C . This means that there is a **circle having its center at the circumcenter** and passing through all three vertices of the triangle.

The centroid of a triangle is the point where the three medians coincide. The centroid theorem states that **the centroid is 23 of the distance from each vertex to the midpoint of the opposite side**.

If **the orthocenter’s triangle is acute, then the orthocenter is in the triangle**; if the triangle is right, then it is on the vertex opposite the hypotenuse; and if it is obtuse, then the orthocenter is outside the triangle.

The Angle Bisector Equidistant Theorem states that any point that is on the angle bisector is an equal distance (“equidistant”) from the two sides of the angle. The converse of this is **also true**.

The Alternate Interior Angles Theorem states that, **when two parallel lines are cut by a transversal , the resulting alternate interior angles are congruent** .

We know that the sum of all three interior angles is always **equal to 180 degrees** in a triangle. Similarly, this property holds for exterior angles as well. Also, each interior angle of a triangle is more than zero degrees but less than 180 degrees. The same goes for exterior angles.

**The sum of the lengths of any two sides of a triangle is greater than the length of the third side**.

The converse of the hinge theorem is also true: If **the two sides of one triangle are congruent to two sides of another triangle**, and the third side of the first triangle is greater than the third side of the second triangle, then the included angle of the first triangle is larger than the included angle of the second …