3-1 Lines and Angles

Quick Review

A transversal is a line that intersects two or more coplanar lines at distinct points.

Image Long Description

• ∠ 1 angle 1  and ∠ 3 angle 3  are corresponding angles.
• ∠ 2 angle 2  and ∠ 6 angle 6  are alternate interior angles.
• ∠ 2 angle 2  and ∠ 3 angle 3  are same-side interior angles.
• ∠ 4 angle 4  and ∠ 8 angle 8  are alternate exterior angles.

Example

Name two other pairs of corresponding angles in the diagram above.

• ∠ 5 angle 5  and ∠ 7 angle 7
• ∠ 2 angle 2  and ∠ 4 angle 4

Exercises

Identify all numbered angle pairs that form the given type of angle pair. Then name the two lines and transversal that form each pair.

Image Long Description

7. alternate interior angles
8. same-side interior angles
9. corresponding angles
10. alternate exterior angles

Classify the angle pair formed by ∠ 1 angle 1  and ∠ 2 . angle 2 .

3-2 Properties of Parallel Lines

Quick Review

If two parallel lines are cut by a transversal, then

• corresponding angles, alternate interior angles, and alternate exterior angles are congruent
• same-side interior angles are supplementary

Example

Which other angles measure 110?

• ∠ 6 angle 6  (corresponding angles)
• ∠ 3 angle 3  (alternate interior angles)
• ∠ 8 angle 8  (vertical angles)

Exercises

Find m ∠ 1 m angle 1  and m ∠ 2 . m angle 2 .  Justify your answers.

13. 
14. 

15. Find the values of x and y in the diagram below.

    

Table of Contents