Page 1: Introduction to Lines and Line Segments
This page introduces the basic concepts of lines and line segments in geometry.
Definition: A prosta (straight line) is a line on a plane that extends infinitely in both directions without a beginning or end.
Straight lines are typically represented in diagrams by showing a portion of the line, as it's impossible to show its infinite extent on paper.
Vocabulary: A półprosta (ray) is a portion of a line that has a fixed starting point but extends infinitely in one direction.
Rays are denoted using two capital letters, with the starting point listed first. For example, "półprosta AB" represents a ray starting at point A and extending through point B.
Definition: An odcinek (line segment) is a portion of a line with a definite beginning and end point.
Line segments are denoted using two capital letters representing their endpoints, such as "odcinek AB".
The page also introduces the concept of parallel lines:
Definition: Proste równoległe (parallel lines) are lines in the same plane that never intersect, maintaining a constant distance from each other at all points.
Parallel lines are symbolized using the "||" notation.
Example: In the diagram, lines a and b are parallel, denoted as a || b.