Investigate the distance between two points, a point and a line, and two lines.

• Students will be able to recognize that the distance between two parallel lines is constant.
• Students will identify segments that represent the distance between two points, a point and a line, and parallel lines.

• parallel lines
• perpendicular lines
• distance
• coinciding points

This lesson involves working with parallel lines and identifying distances between various points and lines. As a result students will:

• Manipulate points and segments to determine that the distance between a point and a line is the length of the shortest segment from the point to the line.
• Manipulate lines to make them parallel, then move a segment and observe that the measured distance between the two lines is constant.
• Use informal deductive language to construct arguments about the distance between points and lines.