Question 19.55

25. Determine whether each of the following statements is always or sometimes true. Drawing some sketches may be helpful.

  1. A line reflection preserves collinearity of points. That is, if the points , , and are in a straight line (collinear), then their images reflected in some other line also lie in a straight line.
  2. A line reflection preserves betweenness. That is, if the collinear points , , and (with between and ) are reflected about a line, then the image of is between the images of and .
  3. The image of a line segment under a line reflection is a line segment of the same length.
  4. The image of an angle under a line reflection is an angle of the same measure.
  5. The image of a pair of parallel lines under a line reflection is a pair of parallel lines.

25.

All are always true.