# Activities

• • • ##### Subject Area

• Math: Geometry: Triangles

• ##### Author 9-12

30 Minutes

• ##### Software

Cabri Geometry™

• ##### Report an Issue

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