Education Technology

Polygons and Vectors

Published on 06/09/2008

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