A proof of the Alternate Interior Angles Theorem, using parallel lines a and b with transversal m, is shown below. Given: alb
m is the transversal.
Prove: 23 25
12
43
5 6
8 7
Proof:
Statements
Reasons
1. Lines a and bare parallel with 1. Given
transversalm
2. 21 - 25
2. Corresponding Angles Postulate
3.23* 21
3. Vertical Angles Theorem
4.23 - 25
Which property is used in step 4?
reflexive property
transitive property
associative property
commutative property