Education Technology

# Activities

• ##### Subject Area

• Math: Geometry: Quadrilaterals and Polygons
• Math: Geometry: Vectors

9-12

60 Minutes

• ##### Device
• TI-89 / TI-89 Titanium
• TI-92 Plus / Voyage™ 200

TI Connect™

• ##### Accessories

TI Connectivity Cable

• ##### Other Materials
This is Activity 7 from the EXPLORATIONS Book:
Geometric Investigations on the Voyage 200 with Cabri

## Polygons and Vectors

#### Activity Overview

Students understand the concepts of vectors and their resultant. They get acquainted with the parallelogram law of vector addition.

#### Before the Activity

• See the attached PDF file for detailed instructions for this activity
• Print page 32 from the attached PDF file for your class
• #### During the Activity

Distribute the page to the class.

Follow the Activity procedures:

• Construct a triangle and label its vertices
• Place a point P anywhere on the screen
• Create three vectors from P to the vertices of the triangle
• Find the resultant of two vectors and determine its endpoint
• Notice that the resultant vector passes through the centroid of the triangle
• Connect the resultant endpoint, Point P, and the vertices containing the vectors, to form a quadrilateral
• Note that the quadrilateral formed is a parallelogram
• Observe that the diagonals of the parallelogram are the side of the triangle and the resultant vector
• Find the vector sum of the three initial vectors and determine the relationship between the triangle and the vector sum
• Examine the relationship between the resultant vector and point P, for various locations of point P
• #### After the Activity

Review student results:

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