1. 14. AB // DE 2 and 7
15. AB and CF 1 and 5
16. BD  DF transv.: l; corr. s
17. Plane ABC // plane DEF transv.: n; alt. int. s
18. 2 and  transv.: m; alt. ext. s
19. 1 and  lines are skew
20. 1 and  B G C
21. 2 and  F D
22. transv.: p; corr s C = cm; A = 20,106.2 cm2
23. transv.: q; alt. int. s C = 11.9 m; A = 11.3 m2
24. transv.: l; alt. ext. s Rt s  or vert s 
25. transv.: p; same-side int. s Linear Pair Theorem
27. corr s Vert s 
28. alt. int. s
29. same-side int. s
35. 8 and 5

2. Warm Up
Identify each angle pair.
1. 1 and 3
2. 3 and 6
3. 4 and 5
4. 6 and 7
corr. s
alt. int. s
alt. ext. s
same-side int s

3. Example 1
Find mQRS.
x = 118
mQRS + x = 180°
mQRS = 180° – x
= 180° – 118°
= 62°

4. Example 2: Music Application
Find x and y in the diagram.
By the Alternate Interior Angles
Theorem, (5x + 4y)° = 55°.
By the Corresponding Angles Postulate, (5x + 5y)° = 60°.
5x + 5y = 60
–(5x + 4y = 55)
y = 5
Subtract the first equation from the second equation.
Substitute 5 for y in 5x + 5y = 60. Simplify and solve for x.
5x + 5(5) = 60
x = 7, y = 5

5. Geometry 3.2 Angles Formed by Parallel Lines and Transversals
Example 3
Find the measures of the acute angles in the diagram.
By the Alternate Exterior Angles
Theorem, (25x + 5y)° = 125°.
By the Corresponding Angles Postulate, (25x + 4y)° = 120°.
An acute angle will be 180° – 125°, or 55°.
The other acute angle will be 180° – 120°, or 60°.