From the course: Test Prep: GRE
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Parallel lines
- [Voiceover] So, parallel lines by one definition are lines that just kind of run along to infinity and never intersect. And, you can kind of look at them and realize, hey, those lines are parallel. So, parallel lines can sometimes come into play in geometry if they are crossed by what we call a transversal. So if I drew a line kind of going through my parallel lines, some interesting things happen with the angles that you should know. So, if you notice this angle up here, let's just call it X, X degrees, we would know that this angle down here is also gonna be X degrees, because the lines are parallel. It's just kind of a rule, and it's a visual rule. I think it's best explained by looking at it. Then, we would also know that because of vertical angles, remember if we make sort of an X, this angle and this angle will be the same. And then, this angle and this angle will be the same. So, we have that going on here. We have X here, and then, this angle will also be X. We can do the…
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Point, lines, segments, and planes1m 29s
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Angles2m 4s
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Parallel lines2m 19s
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Polygons2m 37s
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Triangles4m 2s
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Pythagorean theorem3m 11s
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Special right triangles3m 51s
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Area of a triangle2m 30s
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Congruent triangles2m 17s
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Similar triangles2m 40s
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Quadrilaterals4m 30s
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Circles3m 6s
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Circle area and circumference4m 10s
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Boxes5m 1s
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Cylinders3m 26s
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