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PPT – Lines and Angles PowerPoint presentation | free to view - id: 810693-YzVhZ

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Lines and Angles

- Geometry
- Chapter 3, Section 1

Notes

- What does it mean for two lines to be parallel?
- Parallel lines Lines that do not intersect and

are coplanar. - What about lines that do not intersect and are

not coplanar? - Skew Lines Lines that do not intersect and are

not coplanar. - What does it mean for two planes to be parallel?
- Parallel Planes planes that do not intersect.
- Example the planes containing the ceiling and

floor are parallel

Notes

- Parallel Postulate
- If there is a line and a point not on the line,

then there is exactly one line through the point

parallel to the given line. - Parallel lines have the same slope (line P slope

3 and Line m slope 3) - Tilted at the same angle
- Perpendicular Postulate
- If there is a line and a point not on the line,

then there is exactly one line through the point

perpendicular to the given line. - Perpendicular lines have slopes that are negative

reciprocals (line k slope 4 and line Q slope

1/4) - At 90 degrees from each other

Notes

- Transversal a line that intersects two or
- more lines in a plane at different points.
- E.g. Line c is a transversal to lines a and b.
- Line b is a transversal to which two other lines?

- a c
- How about line a?
- b c
- When a transversal
- intersects two lines,
- how many angles are
- formed?
- 8 angles are formed

Notes

- Angles formed by a transversal.
- We give certain pairs of these angles special

names. - Exterior Angles 1, 2, 7, 8
- Interior Angles 3, 4, 5, 6
- Corresponding Angles 1 5 2 6 3 7 4

8 - Alternate Exterior Angles 1 8 2 7
- Alternate Interior Angles 3 6 4 5
- Consecutive Interior Angles 4 6 3 5

Notes

- Symbols for parallel in statements and figures
- The symbol means is parallel to
- The pink arrows on lines PQ and RS indicate that

they are parallel.

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