Question

If we know that one side of the rectangle is 8 cm can we construct a unique rectangle?

Answer 1

A rectangle is a quadrilateral with equal opposite sides and adjacent sides perpendicular to each other. Since we only know one side of the rectangle we can draw infinite rectangles. Because the other side's length is not specified.
e.g.

In above rectangle, PS = QR = AD = BC = 5cm

So, we can't draw a unique rectangle