Final answer:
The best choice for placing a vertex of a parallelogram in the coordinate plane is at the origin, where the x-axis and the y-axis intersect.
Step-by-step explanation:
The student has asked where to place a vertex of a parallelogram in the coordinate plane. When we deal with two-dimensional vector problems, it is most efficient to use a coordinate system with a horizontal axis (the x-axis) and a vertical axis (the y-axis). A convenient choice for the location of a vertex of a parallelogram would be at the origin, which is where the x-axis and the y-axis intersect. Placing a vertex of the parallelogram at the origin simplifies calculations, as we use the origin as a reference point for measuring distances horizontally and vertically.