$\"\"$

The given vertices of the quadrilateral are $\"\"$ .

Find the slopes of opposite sides.

The slope formula is $\"\"$ .

Slope of $\"\"$ (Substitute $\"\"$ )

Slope of $\"\"$ (Substitute $\"\"$ ) $\"\"$

Since $\"\"$ , quadrilateral EFGH is a parallelogram.

But the product of the slopes of consecutive sides is $\"\"$ .

This means the consecutive sides are not perpendicular.

$\"Graph$

So, the quadrilateral is not a rectangle. $\"\"$

The quadrilateral EFGH is not a rectangle.