Question

identify the reason that justifies the following statement. \m∠abd + m∠dbc = m∠abc\
addition property
definition of angle bisector
angle addition postulate
definition of congruence

Explanation:

The angle - addition postulate states that if point D lies in the interior of ∠ABC, then m∠ABD + m∠DBC=m∠ABC.

Answer:

Angle addition postulate