Reflections over Parallel Lines: Distances
- Bob Allen
Instructions for the first set of reflections.
Distance from a point to a line
1. Why are the two distances, DE and Df, the same? (And if they're not the same, you have done something incorrect. Go back and try again. Remember, nothing has exploded. Not even your grade.) Hint: What distance are we measuring from a point to a line?
2. Measure the distance from A to A''. Record the distance between the lines (either DE or Df) and AA'' in the box below and call it 'Trial 1." Then move any or all of the following objects: the pink dots on line f, point D, or ABC. Record the distance between the lines and AA'' and label it Trial 2 in the box below. Repeat the previous step three more times, labelling new steps as Trials 3 through 5 respectively. Your data should look something like this: Trial 1 ### ### Trial 2 ### ### and so on.
Compare the two distances recorded in the five trials above. State a conjecture about the two distances. Here's a start... If a figure is reflected over two parallel lines, then...