Question 1:
Statement Reasons
m∠ABD + m∠DBC = m∠ABC Angle addition postulate
60° + 40° = m∠ABC Substitution Property of equality
100° = m∠ABC Simplpifying
∠ABC is an obtuse angle Definition of obtuse angle
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Question 2:
Statement Reasons
AC = BD Given
AC = BC + BD Segment addition postulate
AB + BC = BC + CD Addition property of equality
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Question 3:
Angle congruence postulate
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Question 4:
Segment congruence postulate
