Question 814556
<ol><li>Draw four points in the shape of some quadrilateral.</li><li>Label the four points A, B, C and D.<ol><li>Any point can be A.</li><li>Then go clockwise (or counterclockwise) to the next point and label it B.</li><li>Continue on the same direction to the next point and label it C.</li><li>Label the last point D</li></ol></li><li>Draw the last three vectors: BC, CD and DA. (Remember, the first letter is where the arrow starts and the second letter is where the arrowhead is.)</li><li>If you look at these last three vectors and if you understand vector addition, you will see that the sum of these three vectors is BA!</li><li>So BA + (BC+CD+DA) = BA + BA = 2BA</li></ol>