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Ch 4.3. Transversals & Corresponding Angles. Learning Target: I will be able to use theorems to determine the relationships between specific pairs of angles and to use algebra to find angle measurements. Standard 7.0
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Ch 4.3 Transversals & Corresponding Angles Learning Target: I will be able to use theorems to determine the relationships between specific pairs of angles and to use algebra to find angle measurements Standard 7.0 Students prove and use theorems involving the properties of parallel lines cut by a transversal. Ch 4.3Transversals andCorresponding Angles
Ch 4.3 Transversals & Corresponding Angles Postulate 4-1 Concept
Ch 4.3 Transversals & Corresponding Angles Use Corresponding Angles Postulate A. In the figure, m11 = 51. Find m15. Tell which postulates (or theorems) you used. 15 11 Corresponding Angles Postulate m15 =m11 Definition of congruent angles m15 =51 Substitution Answer: m15 = 51 Example 1
Ch 4.3 Transversals & Corresponding Angles Use Corresponding Angles Postulate B. In the figure, m11 = 51. Find m16. Tell which postulates (or theorems) you used. 16 15 Vertical Angles Theorem 15 11 Corresponding Angles Postulate 16 11 Transitive Property () m16 = m11 Definition of congruent angles m16 = 51 Substitution Answer: m16 = 51 Example 1
Ch 4.3 Transversals & Corresponding Angles Classwork #1 A. In the figure, a || b and m18 = 42. Find m22. A. 42 B. 84 C. 48 D. 138 Example 1a
Ch 4.3 Transversals & Corresponding Angles Classwork #1 B. In the figure, a || b and m18 = 42. Find m25. A. 42 B. 84 C. 48 D. 138 Example 1b
Ch 4.3 Transversals & Corresponding Angles 4-1 4-2 4-3 Concept
Ch 4.3 Transversals & Corresponding Angles Concept
Ch 4.3 Transversals & Corresponding Angles Use Theorems about Parallel Lines FLOOR TILES The diagram represents the floor tiles in Michelle’s house. If m2 = 125, find m3. 2 3 Alternate Interior Angles Theorem m2 =m3 Definition of congruent angles 125 =m3 Substitution Answer:m3 = 125 Example 2
Ch 4.3 Transversals & Corresponding Angles Classwork #2 FLOOR TILES The diagram represents the floor tiles in Michelle’s house. If m2 = 125, find m4. A. 25 B. 55 C. 70 D. 125 Example 2
Ch 4.3 Transversals & Corresponding Angles Find Values of Variables A. ALGEBRA If m5 = 2x – 10, and m7 = x + 15, find x. 5 7 Corresponding Angles Postulate m5 =m7 Definition of congruent angles 2x – 10 =x + 15 Substitution x – 10= 15 Subtract x from each side. x = 25 Add 10 to each side. Answer:x = 25 Example 3
Ch 4.3 Transversals & Corresponding Angles Find Values of Variables B. ALGEBRA If m4 = 4(y – 25), and m8 = 4y, find y. 8 6 Corresponding Angles Postulate m8 = m6 Definition of congruent angles 4y = m6 Substitution m6 + m4 = 180 Supplement Theorem 4y + 4(y – 25) = 180 Substitution 4y + 4y – 100 = 180 Distributive Property 8y = 280 Additive Inverse Property. y = 35 Multiplicative Inverse Property. Example 3
Ch 4.3 Transversals & Corresponding Angles Classwork #3 A. ALGEBRA If m1 = 9x + 6, m2 = 2(5x – 3), and m3 = 5y + 14, find x. A.x = 9 B.x = 12 C.x = 10 D.x = 14 Example 3
Ch 4.3 Transversals & Corresponding Angles Classwork #3 B. ALGEBRA If m1 = 9x + 6, m2 = 2(5x – 3), and m3 = 5y + 14, find y. A.y = 14 B.y = 20 C.y = 16 D.y = 24 Example 3
Ch 4.3 Transversals & Corresponding Angles Theorem 4-4 Concept