Question

given: ∠abc is a right angle, ∠dbc is a straight angle. prove: ∠abc≅∠abd. what is the missing reason in the proof? definition of angle bisector definition of congruent angles transitive property segment addition property. statements reasons 1. ∠abc is a right angle 1. given 2. ∠dbc is a straight angle 2. given 3. m∠abc = 90 3. definition of right angle 4. m∠dbc = 180 4. definition of straight angle 5.

Explanation:

Since ∠ABC and ∠ABD both equal 90° (from given right - angle and straight - angle facts), by definition of congruent angles (angles with equal measures are congruent), they are congruent.

Answer:

definition of congruent angles