CK-12 Geometry-Concepts

http://www.ck12.org Chapter 3. Parallel and Perpendicular Lines

Answers:

1. These are Same Side Interior Angles. So, if they add up to 180◦, thenl||m. 113◦+ 67 ◦= 180 ◦, thereforel||m.


2. The given angles are same side interior angles. Because the lines are parallel, the angles add up to 180◦.

( 2 x+ 43 )◦+( 2 x− 3 )◦= 180 ◦

( 4 x+ 40 )◦= 180 ◦

4 x= 140

x= 35

3. These are same side interior angles so set up an equation and solve forx. Remember that same side interior angles
   add up to 180◦.

( 3 x+ 12 )◦+( 5 x+ 8 )◦= 180 ◦

( 8 x+ 20 )◦= 180 ◦

8 x= 160

x= 20

Interactive Practice

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Explore More

For questions 1-2, determine if each angle pair below is congruent, supplementary or neither.

1.^6 5 and^68
2.^6 2 and^63
3. Are the lines below parallel? Justify your answer.