September 17, 2019

warm-up:

Identify the type of angles.

1. ∠C and ∠G

2. ∠D and ∠E

3. ∠A and ∠H

4. ∠D and ∠F

5. ∠D and ∠A

6. ∠H and ∠F

September 17, 2019

Geometry 2.5 Use Parallel Lines and Transversals

When sunlight enters a drop of rain, different colors of light leave the drop at different angles.

Goal: I can classify and calculate angles formed by parallel lines and transversals [G.CO.9]

Tiling Activity

September 17, 2019

If //, corresp. ∠s ≅_______ = _______

If //, alt. ext. ∠s ≅_______ = _______

If //, alt. int. ∠s ≅_______ = _______

If //, same-side int. ∠s suppl._______ + _______ = 180º

_______ = _______

_______ + _______ = 180ºlinear pairs are suppl.

f corr c'sare

September 17, 2019

Corresponding Angles

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

If ||, corresp. ∠s ≅

Da

O

September 17, 2019

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

Alternate Exterior Angles

If ||, alt. ext. ∠s ≅

September 17, 2019

Alternate Interior Angles

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

If ||, alt. int. ∠s ≅

September 17, 2019

Consecutive Interior(Same-Side Interior) Angles:

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

If ||, same-side int. ∠s supplementary

Addupto

1800

September 17, 2019

Justify your answer.

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

vertical ∠s ≅linear pairs are suppl.

If ||, corresp. ∠s ≅ If ||, same-side int. ∠s suppl.

450

700 go

egrets srsiguptp go as

September 17, 2019

Justify your answer.

If ||, alt. ext. ∠s ≅

If ||, alt. int. ∠s ≅vertical ∠s ≅ linear pairs are suppl.

If ||, same-side int. ∠s suppl.If ||, corresp. ∠s ≅

6.590I

1100

alt int L's alt ex c'sare I are 7

September 17, 2019

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

vertical ∠s ≅

linear pairs are suppl.

If ||, corresp. ∠s ≅

1

2

3

4

100˚6.

If ||, same-side int. ∠s suppl.

m∠1 = ______˚

m∠2= ______˚

m∠3 = ______˚

m∠4 = ______˚

80 Fr80100 90

80 90

September 17, 2019

7.

7575

75y 105

September 17, 2019

8.

135o

(x – 30)o

y˚

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

Solve for x:

Solve for y:

Solve for x:_______________Eqn:_____________________

_______________Eqn:_____________________

_______________Eqn:_____________________

lineffircorr Sint Jssint

use corr Ls

X 30 135X 165 3 91 5 25 180

use linear pair8 16 180

41 135 180 8x 196

y 45 X 24,5

September 17, 2019

Assignment: 2.5 worksheet

If ||, corresp. ∠s ≅

If ||, alt. int. ∠s ≅If ||, same-side int. ∠s are supplementary

If ||, alt. ext. ∠s ≅

Vert. ∠s ≅Linear Pairs are supplementary

Summary

(If ||, consecutive int. ∠s are supplementary)

September 17, 2019

Geo 2.5 wksht answers1. 65˚, If ||, then corr ∠s are ≅2. 71˚, If ||, then alt-int ∠s are ≅3. 63˚, If ||, then same- side int ∠s are supp.4. 120˚, If ||, then alt-ext ∠s are ≅5. 125˚, If ||, then linear pairs are supp.

6. 150˚; If ||, then corr ∠s are ≅ 150˚; vert ∠s are ≅

7. 122˚; If ||, then alt-int ∠s are ≅ 58˚; If ||, then same- side int ∠s are supp.

8. m∠1 = 90˚, m∠2 = 115˚ m∠3 = 65˚

9. m∠1 = 100˚, m∠2 = 80˚ m∠3 = 100˚

10. corresponding ∠s x = 7

11. same-side int ∠s x = 4

12. alt-int ∠s x = 8

13. alt-ext ∠s x = 6

14. linear pair x = 9

15. vertical ∠s x = 12

16. x = 145, y = 15 17. x = 20, y= 10