150 likes | 247 Views
Properties of Parallel Lines. Check Skills You’ll need. Solve each equation x + 2x + 3x = 180 (w+23)+(4w+7)=180 90=2y – 30 180 – 5y = 135 Write an equation and solve the problem 5. The sum of m /_ 1and twice its complement is 146.
E N D
Check Skills You’ll need Solve each equation • x + 2x + 3x = 180 • (w+23)+(4w+7)=180 • 90=2y – 30 • 180 – 5y = 135 Write an equation and solve the problem 5. The sum of m/_ 1and twice its complement is 146. 6. The measures of two supplementary angles are in the ratio 2:3. Find their measures.
What is a transversal? A transversal is a line that intersects two coplanar lines at two distinct points. The diagram shows the eight angles formed by a transversal t and two lines l and m. t 5 6 l 1 3 m 4 2 7 8
1 3 alternate interior angles 4 2 1 same-side interior angles 3 4 2
5 6 1 3 4 2 7 8 corresponding angles
Postulate 3-1 If a transversal intersects two parallel lines, then corresponding angles are congruent. 5 6 1 3 4 2 7 8
Theorem 3 – 1 If a transversal intersects two parallel lines, then alternate interior angles are congruent. 1 3 4 2
Theorem 3-2 If a transversal intersects two parallel lines, the same-side interior angles are supplementary 1 3 4 2
Proving If a transversal intersects two parallel lines, then alternate interior angles are congruent. Given: a ||b Prove: /_ 1 = /_ 3 4 3 1 1. a|| b given 2. /_ 1 = /_ 4 Corresponding Angles Postulate 3. /_ 4 = /_ 3 Vertical angles 4. /_ 1 = /_ 3 Transitive property
Proving If a transversal intersects two parallel lines, then alternate interior angles are congruent. Given: a ||b Prove: /_ 1 = /_ 2 are supplementary 3 2 1
Find the measures of all the angles f a 3 e b 50 g h c d
Find the values of x and y 50 70 x y
Your most awaited part It’s TEST TIME