Copy the vector diagram on graph paper.
Draw vectors equivalent to r and q so that you can add them easily.
Draw and label the resultant vector, r + q.
Using the same initial point, draw and label q + r.
Move vectors r and q above to show q + r.
The quadrilateral you just drew has a special name. What is it?
Challenge: You can prove that r + q = q + r by proving that your answer to part (d) is true. Use what you remember from geometry to justify the special name.