91Ó°ÊÓ

$\text{O}\left(0,0\right)\text{,E}\left(4,0\right)\text{,F}\left(4,3\right)\text{,G}\left(\underset{¯}{?},\underset{¯}{?}\right)$

The coordinates of the three vertices are shown in the graph below. Since the three points $\text{O}\left(0,0\right)\text{,E}\left(4,0\right)\text{,F}\left(4,3\right)$ are given to be a part of a rectangle, the fourth vertex G must have the coordinates in a way for the four points to form a rectangle.

It has been specified that the three given vertices are that of a rectangle and it is been plotted as in the above figure. So, based on the property of the rectangle, every angle should be a right angle and this brings in a restriction on the location of the fourth vertex.

As visible from the graph, the fourth vertex has to be $G\left(0,3\right)$and the resulting quadrilateral is a rectangle itself. It cannot be a square since the sides are not equal.

Therefore,

The coordinates of the fourth vertex is $G\left(0,3\right)$.

The resulting figure is a rectangle.