Question

Writing a Two-Column Proof

Answer 1

For the blank on the left, the answer is "angle ABC" without quotes of course. This is because we're using the substitution property which is the reasoning for statement 4. To elaborate, we connect statement 1 and statement 3 to get to statement 4.

The last statement, statement 5, is simply a repeat of the claim we want to prove. So you'll just copy/paste where it says "prove" as your last statement. Always start with the "given" and end up with "prove" is how I think of it.

The reasoning for the last statement is "definition of congruence". If two angles are congruent, then they have the same angle measure.