Download Definition of Angle Bisector Substitution Property of Equality Division

GEOMETRY
Angle Bisector Theorem NAME_________________________
DATE __________ Per.___________
Proofs
the Angle
3. Construct
Bisector of ∠BIC.
B
I
Measure the angles:
m∠BIS =
m∠SIC =
m∠BIC =
How are the measures
related?
Label it as ray IS.
C
4. Fill in the Statements in this flowchart proof:
5.
Given: IS bisects ∠BIC.
Prove: m∠BIS = 1 m∠BIC and m∠SIC = 1 m∠BIC.
2
Draw the arrows to show the
logical flow of the proof from
bubble to bubble.
2
m∠BIS =
____________
GIVEN
Definition of Angle
Bisector
m∠BIS + m∠____ = m∠BIC
= 2m∠__ __ __ and
m∠____ + m∠___ = m∠____
= 2m∠SIC
m∠____
+ m∠____ = m∠____
_______________________
Angle Addition
Postulate
Substitution Property of
Equality
m∠BIS =
and
m∠____ = 1 m∠BIC
2
Division Property
of Equality