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(over Lesson 9-4). 1-1a. Slide 1 of 2. (over Lesson 9-4). 1-1b. Slide 1 of 2. Vocabulary. Triangles and Parallel Lines. What You'll Learn. You will learn to use proportions to determine whether lines are parallel to sides of triangles. Nothing New!. A. 6. 4. C. B. 9. 6. D. E.
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(over Lesson 9-4) 1-1a Slide 1 of 2
(over Lesson 9-4) 1-1b Slide 1 of 2
Vocabulary Triangles and Parallel Lines What You'll Learn You will learn to use proportions to determine whether lines are parallel to sides of triangles. Nothing New!
A 6 4 C B 9 6 D E Triangles and Parallel Lines You know that if a line is parallel to one side of a triangle and intersects the other two sides, then it separates the sides into segments of proportional lengths (Theorem 9-5). The converse of this theorem is also true.
A x D E 2x C B Triangles and Parallel Lines one-half
8 5 8 5 Triangles and Parallel Lines Use theorem 9 – 7 to find the length of segment DE. A x 11 D E 22 C B
M 1) MP || ____ A B AC N P C Triangles and Parallel Lines A, B, and C are midpoints of the sides of ΔMNP. Complete each statement. 28 2) If BC = 14, then MN = ____ s 3) If mMNP = s, then mBCP = ___ 4) If MP = 18x, then AC = __ 9x
E 8 A B 5 7 D F C Triangles and Parallel Lines A, B, and C are midpoints of the sides of ΔDEF. 1) Find DE, EF, and FD. 14; 10; 16 2) Find the perimeter of ΔABC 20 3) Find the perimeter of ΔDEF 40 4) Find the ratio of the perimeter of ΔABC to the perimeter of ΔDEF. 1:2 20:40 =
D F G is the midpoint of BA E is the midpoint of AD H is the midpoint of CB C F is the midpoint of DC E H A G B Q1) What can you say about EF and GH ? (Hint:Draw diagonal AC .) Triangles and Parallel Lines ABCD is a quadrilateral. They are parallel Q2) What kind of figure is EFHG ? Parallelogram
Triangles and Parallel Lines End of Section 9.5