2.4: Special Angles on Parallel Lines WELCOME 2.4: Special Angles on Parallel Lines Last Night’s Homework: Tonight’s Homework:

Warm-Up Solve for x: 2. Solve for x: 𝟏 𝟒 +𝟓𝒙= 𝒙 𝟑 80 2x+60

Chapter 2 Section 4

Transversal line Line that intersects “crosses” two or more coplanar lines J K L “J is transversal of K & L”

Transversal lines and their angles Corresponding: Occupy the same position Alternate Exterior: Outside and Opposite sides 1 3 2 4 Alternate Interior: Inside and Opposite sides Same Side Interior: Inside and same sides 7 5 6 8

Corresponding Angles ∠1 ≌ ∠2 If two ‖ lines are cut by a transversal, then corresponding angles are congruent 1 2 ∠1 ≌ ∠2

Alternate Exterior ∠ ∠7 ≌ ∠8 If two ‖ lines are cut by a transversal, then alternate exterior angles are congruent 7 8 ∠7 ≌ ∠8

Alternate Interior ∠ ∠3 ≌ ∠4 If two ‖ lines are cut by a transversal, then alternate interior angles are congruent 3 4 ∠3 ≌ ∠4

Same Side Interior ∠ ∠5 + ∠6 = 180° If two ‖ lines are cut by a transversal, then the two same side interior angles are supp. (180°) 5 6 ∠5 + ∠6 = 180°

Biconditional ǁ line Relationship Corresponding : Occupy the same position Alternate Exterior : Outside and Opposite sides 1 3 ≌ iff ‖ ≌ iff ‖ 2 4 Alternate Interior : Inside and Opposite sides Same Side Interior : Inside and same sides 7 5 ≌ iff ‖ Supp. iff ‖ 6 8

Perpendicular Transversal If a transversal is perpendicular to one of two ‖ lines, then it is perpendicular to the other line J K L K ⊥ L

Practice: