4. Addition of vectors. Vector r has a magnitude of 5.6 km and points due East. Vector r2 has a magnitude of 7.2 km and points due South. Vector r3 has a magnitude of 11.0 km and points due West. Vector r4 has a magnitude of 10.8 km and points due North. a. On the grid below, show the addition of r, 12, 13, and r4, using the tip-to-tail method. Make sure to show the resultant vector on your diagram. Use a scale factor of 1 km per grid line. Use a protractor and ruler to make sure your vectors have the correct magnitude and direction. b. Use a ruler to measure the length of your resultant vector. Use the scale factor to convert this to a magnitude to km. c. Use a protractor to measure the direction of your resultant vector.