Final answer:
The coordinates of the upper right vertex of the rectangle are (a,a).
Step-by-step explanation:
To label the upper right vertex of the rectangle, we know that the longer side of the rectangle is along the x-axis and the lower left vertex is at the origin (0,0). The upper left vertex is labeled as (0,a), so the y-coordinate is a. Since the longer side of the rectangle is along the x-axis, the y-coordinate of the upper right vertex will be the same as the y-coordinate of the upper left vertex, which is a.
Therefore, the coordinates of the upper right vertex of the rectangle are (a,a).