Answer:
Not a parallelogram.
Step-by-step explanation:
By the midpoint formula, the midpoint of a segment between [tex](x_{0},\, y_{0})[/tex] and [tex](x_{1},\, y_{1})[/tex] is:
[tex]\begin{aligned} \left(\frac{x_{0} + x_{1}}{2},\, \frac{y_{0} + y_{1}}{2}\right)\end{aligned}[/tex].
A quadrilateral is a parallelogram if and only if the midpoints of the two diagonals are the same.
The two diagonals of quadrilateral [tex]{\sf ABCD}[/tex] are segment [tex]\sf{AC}[/tex] and segment [tex]{\sf BD}[/tex], respectively.
Using the midpoint formula, the midpoint of segment [tex]{\sf AC}[/tex] (between [tex]{\sf A}\; (3,\, 3)[/tex] and [tex]{\sf C}\; (-3,\, 1)[/tex]) would be:
[tex]\begin{aligned} & \left(\frac{3 + (-3)}{2},\, \frac{3 + 1}{2}\right) \\ =\; & (0,\, 2)\end{aligned}[/tex].
Likewise, the midpoint of segment [tex]{\sf BD}[/tex] (between [tex]{\sf B}\; (1,\, 2)[/tex] and [tex]{\sf D}\; (-1,\, 4)[/tex] would be [tex](0,\, 3)[/tex].
Thus, quadrilateral [tex]{\sf ABCD}[/tex] would not be a parallelogram since the midpoints of its two diagonals are not the same.
