Geometry 2.4 and 2.5

Identify Pairs of Lines & Angles

Goal: I can classify angle pairs

and calculate angles formed by parallel lines and transversals.

[G.CO.9]

Parallel lines:

DEFINE ........

rp

s

Perpendicular lines:

Skew lines:

State an example of the following pairs of lines:Parallel lines

Perpendicular lines

Skew lines

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

1 2

3 4

5 6

7 8t

Interior ∠s:

Exterior ∠s:

________ is a transversal

Corresponding Angles

Description:

If lines are ||, then...

equation:

demo

Alternate Exterior Angles

Description:

If lines are ||, then...

equation:

demo

Description:

If lines are ||, then...

Alternate Interior Angles

equation:

demo

Description:

If lines are ||, then...

Consecutive Interior Angles

(same-side interior)

equation:

demo

Corresponding Angles

If 2 parallel lines are cut by a transversal, then corresponding angles are congruent.

Back to def.If //, corresp. ∠s ≅

If 2 parallel lines are cut by a transversal, then alternate exterior angles are congruent.

Alternate Exterior Angles

Back to defIf //, alt. ext. ∠s ≅

Alternate Interior Angles

If 2 parallel lines are cut by a transversal, then alternate interior angles are congruent.

Back to tableIf //, alt. int. ∠s ≅

Consecutive Interior(Same-Side Interior) Angles:

If 2 parallel lines are cut by a transversal, then consecutive (same-side) interior angles are supplementary.

Back to table

If //, consec. int. ∠s supplementary

Classify the pair of numbered angles.

3. 4.

1. 2.

corresponding

alternate exterior

alternate interior

consecutive interior

Justify your answer.

5. 6. 7.

If //, alt. ext. ∠s ≅If //, alt. int. ∠s ≅

vertical ∠s ≅linear pairs are suppl.

If //, corresp. ∠s ≅ If //, consec. int. ∠s suppl.

If //, corresp. ∠s ≅If //, consec. int. ∠s suppl.

If //, corresp. ∠s ≅

If //, alt. ext. ∠s ≅If //, alt. int. ∠s ≅

vertical ∠s ≅linear pairs are suppl.

If //, consec. int. ∠s suppl.

If //, corresp. ∠s ≅

Find the measure of the numbered angles. Justify your answer.9.8.

If //, alt. int. ∠s ≅If //, alt. ext. ∠s ≅

10.

11.

135o

(x – 30)o

y˚

12. Classify the angles type. Then solve for the missing variables.

Solve for x:

Solve for y:

Solve for x:_______________Eqn:_____________________

_______________Eqn:_____________________

type:_____________

Eqn:_____________________

type:

type:

Assignment:

2.4,5 worksheet

If //, corresp. ∠s ≅

If //, alt. int. ∠s ≅

(same-side int. ∠s )

If //, alt. ext. ∠s ≅

Vert. ∠s ≅ Linear Pairs are supplementary

Summary

If //, consec. int. ∠s are supplementary

Assignment: 2.4,5 Parallel lines and Transversal WS

Quiz over 2.1-5 on Friday!

Geometry 2.4,5 Ws Answers

1. parallel

2. perpendicular

3. perpendicular

4. skew

5-8. Answers vary

9.a. corresponding

b. alternate exterior

c. consecutive interior

d. alternate interior

10. 150˚, If || then corr ∠s ≌ 150˚, If ||, alt. ext. ∠s ≌

11. 122˚, If ||, alt int ∠s ≌ 58˚, If || cons int ∠s supp.

12. corr. ∠s ; x = 7

13. cons. int. ∠s ; x = 4

14. alt. int. ∠s ; x =8

15. alt. ext. ∠s ; x = 616. linear pair ; x = 9

17. vertical ∠s ; x =12

#12-16 Show work!

Geometry 2.4,5 Wksht Answers