Education Technology

Slide Along

Published on 06/09/2008

Activity Overview

In this activity, students use the Geoboard to determine the areas of quadrilaterals between parallel lines.

Before the Activity

  • Start the Geoboard App and format it
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 37 - 46 from the attached PDF file for your class
  • During the Activity

    Distribute the page to the class.

    Follow the Activity procedures:

  • Construct two parallel line segments, with a distance of 5 units between them
  • Between these two parallel lines build three different parallelograms with the same base of 1 unit and same height of 5 units
  • Calculate the area of the parallelograms, and observe that it is the same as the area of a rectangle with the same height and base (5 square units)


  • Draw three trapezoids between the parallel lines that have the same bottom base length of 2 units, top base length of 1 unit and height 5 units
  • Calculate the area of the trapezoids
  • Note the area of trapezoids is equal to 7.5 square units
  • Observe that the area of quadrilaterals between parallel lines with same base and height area equal
  • After the Activity

    Review student results:

  • As a class, discuss questions that appeared to be more challenging
  • Re-teach concepts as necessary