Question: Point

Answer: Indicates a location and has no size

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Question: Line

Answer: A straight path that extends in two opposite directions without end and has no thickness; contains infinitely many points.

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Question: Plane

Answer: Represented by a flat surface that extends without end and has no thickness; contains infinitely many lines.

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Question: Collinear Points

Answer: Points that lie on the same line

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Question: Coplanar

Answer: Points and lines that lie in the same plane

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Question: Segment

Answer: Part of a line that consists of two endpoints and all points between them; middle is midpoint.

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Question: Ray

Answer: Part of a line that consists of one endpoint and all the points of the line on one side of the endpoint.

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Question: Opposite rays

Answer: Two rays that share the same endpoint and form a line

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Question: Postulate

Answer: Statement of fact, basic building block of logical systems in geometry.

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Question: Postulate 1-1

Answer: Through any two points there is exactly one line.

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Question: Intersection

Answer: A set of points two or more geometric figures have in common

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Question: Postulate 1-2

Answer: If two distinct lines intersect, then they intersect in exactly one point.

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Question: Postulate 1-3

Answer: If two distinct planes intersect, then they intersect in exactly one line.

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Question: Postulate 1-4

Answer: Through any three noncollinear points there is exactly one plane.

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Question: Undefined Terms

Answer: Points, lines, and planes

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Question: Opposite Rays, AKA…

Answer: Line

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Question: What is the ray’s endpoint in its notation?

Answer: First letter

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Question: Why do you use two arrowheads when drawing or naming a line?

Answer: It continues on in both directions infinitely.

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Question: How is naming a ray similar to naming a line? How is it different?

Answer: A ray goes on infinitely in one direction, whereas a line goes on infinitely in both directions.

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Question: If one ray contains another ray, are they the same ray? Explain.

Answer: Not necessarily, only if they have the same endpoints.

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Question: How many planes contain the same three collinear points? Explain.

Answer: Infinitely many planes may contain the same three collinear points if the planes all intersect at the same line.

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Question: How many planes contain a given line? Explain.

Answer: Infinitely many

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Question: Conjecture

Answer: A statement believed to be true, but not yet proven.

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Question: Axiom

Answer: A rule or statement that is accepted true without a proof.

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Question: T/F? The Earth’s equator is a segment.

Answer: F

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