Angle Bisectors, Midpoints, Segment Bisector

A segment that bisects one of the angles of a triangle

• Angle Bisector

• Perpendicular Bisector

• Altitude

• Midsegment

The figure is an example of a(n) ...

• angle bisector

• perpendicular bisector

• median

• midsegment

The point of concurrency made by 3 angle bisectors is known as the

• orthocenter

• centroid

• circumcenter

• incenter

A segment joining two sides of a triangle at the midpoints.

• altitude

• perpendicular bisector

• midsegment

• angle bisector

Given: m∠LAN = 30⁰ , m∠1 = 15⁰
Prove: AM bisects ∠LAN
Step 1: m∠LAN = 30⁰ 
Step 2: m∠1 + m∠2 = m∠LAN
Step 3: m∠1 + m∠2 = 30⁰
Step 4: m∠1 = 15⁰
Step 5: 15⁰ + m∠2 = 30⁰
Step 6: m∠2 = 15⁰
What is the justification for Step 6?

• Subtraction property of equality

• Substitution

• Addition property of equality

• Definition of congruent angles

RS is the segment bisector.  If OQ = 8x-51 and

PO =3x-6 , find the value of PQ?

• 9

• 28

• 12

• 42

What is reason 1?

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Which of the following below would fill in the Reasons in the proper order?

• Given; Definition of bisect; Transitive; Given, Definition of bisect

• Given; Transitive; Given; Definition of bisect; Definition of bisect

• Given; Definition of bisect; Given; Definition of bisect; Transitive

If DA bisects IE, then

• ID=ED

• IA=EA

• <IDA=<EDA

• <IAD and <EAD are right angles

What is reason 2?

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