How do you prove that this figure is a quadrilateral?
The points are A(1,3) B(3,5) C(9,1) and D(7,1)

Answer:
Yes, it is quadrilateral
Step-by-step explanation: Because Quadrilateral are basic 4 angles on each side of rectangle, they're 90 degrees and Opposite sides equal. It is really similar to Trapezoid.
Quadrilaterals are Rectangle, Square, Rhombus, Parallelogram, Trapezoid, and a Diamond.