Geometry CH 1-3 Segments, Rays, Parallel Lines End of Lecture / Start of Lecture mark.

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Geometry CH 1-3 Segments, Rays, Parallel Lines End of Lecture / Start of Lecture mark 2 4 2 b b ac x a

Transcript of Geometry CH 1-3 Segments, Rays, Parallel Lines End of Lecture / Start of Lecture mark.

Geometry

CH 1-3 Segments, Rays, Parallel Lines

End of Lecture / Start of Lecture mark

2 4

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b b acx

a

Geometry

CH 1-3 Segments, Rays, Parallel Lines

1. 2. 3.

4. the bottom 5. the top

6. the front 7. the back

8. the left side 9. the right side

Judging by appearances, will the lines intersect?

Name the plane represented by each surface of the box.

NO Yes NO

NMR PQL

NKL PQR

PKN LQR

Geometry

CH 1-3 Segments, Rays, Parallel Lines

Geometry

CH 1-3 Segments, Rays, Parallel Lines

• Line: is a series of points going continuously in opposite directions.

• Line AB• Segment: is a part of a line consisting of two end points and

the points between them.• Segment AB

A B Line l

A B

Geometry

CH 1-3 Segments, Rays, Parallel Lines

• Ray is a part of a line consisting of one endpoint and all points on one side of the end point, going continuously in one direction.

• Opposite Rays are two collinear rays with the same endpoint. They always form a line.

Geometry

CH 1-3 Segments, Rays, Parallel Lines

Name the segments in the figure.

The labeled points in the figure are A, B, and C.

A segment is a part of a line consisting of two endpoints and all points between them. A segment is named by its two endpoints.

So the segments are BA (or AB) and BC (or CB).

Geometry

CH 1-3 Segments, Rays, Parallel Lines

Name the segments and rays in the figure.

The labeled points in the figure are A, B, and C.

A ray is a part of a line consisting of one endpoint and all the points of the line on one side of that endpoint. A ray is named by its endpoint first, followed by any other point on the ray. So the rays are BA and BC.

Geometry

CH 1-3 Segments, Rays, Parallel Lines

Identifying Parallel or Skew Lines

• Lines that do not intersect are either Parallel or Skew lines.

• Parallel lines lie on the Same Plane and do not intersect.

Geometry

CH 1-3 Segments, Rays, Parallel Lines

Identifying Parallel or Skew Lines

• Skew lines do not intersect and lie on Different Planes (Non Co-Planar)

• Segments or Rays are parallel or skew iff the lines on which they lie are parallel or skew.

Geometry

CH 1-3 Segments, Rays, Parallel Lines

Use the figure below. Name all segments that are parallel to AE.

Parallel segments lie in the same plane, and the lines that contain them do not intersect. The three segments in the figure above that

are parallel to AE are BF, CG, and DH.

Geometry

CH 1-3 Segments, Rays, Parallel Lines

Use the figure below. Name all segments that are skew to AE.

Skew lines are lines that do not lie in the same plane. The four lines in the figure that do not lie

in the same plane as AE are BC, CD, FG, and GH.

Geometry

CH 1-3 Segments, Rays, Parallel Lines

•Planes are parallel if they do not intersect. If the walls of your classroom are vertical, opposite walls are parts of parallel planes.

•If the ceiling and floor of the classroom are level, they are parts of parallel planes.

Identify a pair of parallel planes in your classroom.

Geometry

CH 1-3 Segments, Rays, Parallel Lines

Use the figure below for Exercises 1-3.

1.Name the segments that form the triangle.

2.Name the rays that have point T as their endpoint.

3.Explain how you can tell that no lines in the figure are parallel or skew.

TO, TP, TR, TS

The three pairs of lines intersect, so they cannot be parallel or skew.

RS, TR, ST

Geometry

CH 1-3 Segments, Rays, Parallel Lines

Use the figure for Exercises 4 and 5.

4. Name a pair of parallel planes.

5. Name a line that is skew to XW.

AC or BD

plane ABCD || plane XWQ