Why is it important to measure perimeter and area

Say you're building a house and the queen of england is going to sleep in one of the rooms and she's got terrible ocd so everything has to be perfect or she'll go crazy. you need to measure the perimeter of the floor to fit in the rug and you need the area of the floor to find out if the bed will fit or if you need a new one. don't know if this is what you're asking but its pretty important.