Question

1. ∠abc is a right angle2. ∠dbc is a straight angle3. m∠abc=90°4. m∠dbc=180°5. m∠abd + m∠abc=m∠dbc6. m∠abd +90°=180°7. m∠abd=90°8. ∠abd is a right angle1. given2. given3. definition of right angle4. definition of straight angle5. angle addition property6. substitution property7. subtraction property8. definition of right angle○ two-column proof○ two-paragraph proof○ flowchart proof○ one-diagram proof

Explanation:

The provided proof is structured with two parallel columns: one for statements (the claims being made) and one for corresponding reasons (justifications for each statement). This matches the defining structure of a two-column proof, which is distinct from paragraph, flowchart, or other proof formats.

Answer:

two-column proof