Education Technology

Cottage Water Problem

Activity Overview

Students use the Cabri Geometry II Plus software to solve a geometry problem. They move the vertex point that is common to two right triangles along the base to find the smallest possible sum of the length of the hypotenuse.

Before the Activity

  • Download the Cabri Geometry™ software on the computer

  • See the attached FIG file for details of this activity

  • During the Activity

    Follow the Activity procedure:

  • For each triangle measure the base angle with the common vertex
  • Drag the common vertex along the base and note where the base angles in both the triangles have the same value
  • With the vertex at this point, measure the hypotenuse of the two triangles
  • Sum of the length of the hypotenuse gives the smallest length of pipe required
  • Verify this value by moving the pump along the river and viewing the total length of the pipes
  • Change the position of the cottages and repeat the activity
  • After the Activity

    Review student results:

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