Complete the proof for theorem 3-13. 1. l||m if lines are ||, corresponding angles are equal. 2. m∠1 = m∠3 vertical angles are equal. 3. m∠2 = m∠3 given 4. m∠1 = m∠2 substitution

To find the proof of this theorem, you need to match column a to column b. The given are the following: This would be column  a: 1. l||m 
2.m∠1 = m∠3 
3.m∠2 = m∠3 
4.m∠1 = m∠2  This would be column b: a. If lines are ||, corresponding angles are equal. 
b. given 
c. substitution 
d. Vertical angles are equal. The theorem is asking us to prove that m1 = m2. So the answers would be:   1.       Would be b because that is the given for the theorem. 2.       The answer is a. 3.       The answer is d. 4.       The answer is c.