Proving Lines are Parallel Unit 3: Day 2. Proving Lines are Parallel

Check Your Skills a ll b If m<2 = 45 Find m<6 If m<1 = 2x + 4 and m<5= 3x – 8. Find the m<1.

Homework Check

70 2. 38 3. 113 4. x=10, m<3 = 80 5. x=47, m<3= 91 6.a) 1&8, 4&7, 2&5, or 3&6 b) 4&5 or 3&8 c) 4&8, 3&5

Proving Lines Parallel Ways to Prove Lines are ll: If corresponding <‘s are If Alternate Interior <s are If Alternate Exterior <s are If Same-Side Interior <s are supplementary If Same-Side Exterior <s are supplementary

Corresponding Angle Postulate If a transversal intersects two parallel lines, then corresponding angles are congruent. Converse of the Corresponding Angle Postulate: If two lines and a transversal form corresponding angles that are congruent, then the two lines are parallel. True

Alternate Interior Angles Theorem: If a transversal intersects two parallel lines, then alternate interior angles are congruent Converse of Alt. Int. <s Theorem: If two lines and a transversal form alt. int. <s that are congruent, then the two lines are parallel.

Same-Side Interior Angle Theorem: If a transversal intersects two parallel lines, then same-side interior angles are supplementary Converse of Same-Side Int. < theorem: If two lines and a transversal form same-side interior angles that are supplementary, then the two lines are parallel.

Are the lines ll? Justify.

Homework: ClassWork Lesson 3-2 Proving Lines Parallel Examples 1-4 and the 4 problems without #’s Need to be checked off for a grade. Homework: Remainder of worksheet