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3.5 Using the Properties of Parallel lines Making Lines Parallel

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Theorem used to use the idea of parallel lines If two lines are parallel to the same line, then they are parallel to each other. If a // b and b // c, then a // c.

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If you were hanging wallpaper. To make sure the pattern is going to up and down and not at an angle; you need parallel lines. With a plumb line, find a vertical line. defined (plumb line n. 1. A line from which a weight is suspended to determine verticality or depth. 2. A line regarded as directed exactly toward the earth's center of gravity.

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If you were hanging wallpaper. To make sure the pattern is going to up and down and not at an angle; you need parallel lines. With a plumb line, find a vertical line. defined (plumb line n. 1. A line from which a weight is suspended to determine verticality or depth. 2. A line regarded as directed exactly toward the earth's center of gravity.

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Plumb line can be made with a piece of string and metal washer. With a pencil mark the line made by the line. Place the edge of your first piece of wallpaper on the line.

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Plumb line can be made with a piece of string and metal washer. With a pencil mark the line made by the line. Place the edge of your first piece of wallpaper on the line.

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Plumb line can be made with a piece of string and metal washer. With a pencil mark the line made by the line. Place the edge of your first piece of wallpaper on the line. Use the edge of the wallpaper for the next edge.

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How do you know the edge are parallel? With a pencil mark the line made by the line. Place the edge of your first piece of wallpaper on the line. Use the edge of the wallpaper for the next edge.

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How do you know the edge are parallel? If two lines are parallel to the same line, then they are parallel to each other. All the edges will be parallel.

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Another Theorem In a plane, if 2 lines are perpendicular to a third line, then they are parallel to each other. If r v and r q, then v // q

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Lets prove it #1. r v and r q#1. Given #2. #2.All right angle congruent #3. v // q#3. If two cut by a transversal and Correspond angles are congruent then the lines are parallel

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Lets prove it #1. r v and r q#1. Given #2. #2.All right angle congruent #3. v // q#3. If two cut by a transversal and Correspond angles are congruent then the lines are parallel

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Lets prove it #1. r v and r q#1. Given #2. #2.All right angle congruent #3. v // q#3. If two cut by a transversal and Correspond angles are congruent then the lines are parallel

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Lets prove it #1. r v and r q#1. Given #2. #2.All right angle congruent #3. v // q#3. If two cut by a transversal and Correspond angles are congruent then the lines are parallel

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Lets prove it #1. r v and r q#1. Given #2. #2.All right angle congruent #3. v // q#3. If two cut by a transversal and Correspond angles are congruent then the lines are parallel

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Homework Page 160 – 163 #8 – 13, 15 – 23 odd 31, , odd, 50

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