Question

given: ∠abc is a right angle, ∠dbc is a straight angle
prove: ∠abd is a right angle

diagram of angles at point b with d, b, c colinear and a perpendicular to bc

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. m∠abd + m∠abc = m∠dbc | 5. angle addition property
6. m∠abd + 90° = 180° | 6. substitution property

what is the format of this proof?

• two - paragraph proof
• flowchart proof
• one - paragraph proof
• two - column proof

Explanation:

The proof in the image has two columns: one for "Statements" and one for "Reasons", which is the characteristic of a two - column proof. A two - column proof organizes statements and their corresponding justifications (reasons) in two separate columns to prove a geometric statement.

Answer:

A. two - column proof