You measure them, using a ruler or tape measure or similar.
The dimensions of the rectangular lot are: 30m by 15m
The word "rectangular" is an adjective, not a noun. So, a "rectangular" cannot exist. The question is like asking for the dimensions of a blue. What you need to do is specify rectangular WHAT! A rectangular pyramid, a rectangular prism, a rectangular dipyramid or some other shape.
A rectangular drop leaf dining table typically has dimensions of around 30 inches in height, 36 inches in width, and 48 inches in length when fully extended. The design features include hinged leaves on each side that can be raised or lowered to adjust the table size, allowing for flexibility in seating and space-saving when not in use.
When measuring for a rectangular tablecloth, naturally measure the length and width you need. Then, add at least half of the height of the table on both dimensions, in order to allow for overlap.
A rectangular prism has 3 dimensions. Whereas the rectangle has only 2 dimensions.
It depends on the dimensions of the rectangular prism.
3
length and width
The dimensions of a rectangular plot are its length and width.
By measuring them!
69
Just knowing the volume in centimeters cubed of a rectangular prism would not allow you to find the dimensions.