If you wanted to redecorate your house, you would need to know how much carpet, paint or wallpaper you would need - you would use area and perimeter to work this out.
No, you can not calculate an area if you know just the perimeter. For example, rectangle with sides of 10 and 20 would have a perimeter of 60 and an area of 200, but a square of sides 15 would have a perimeter of 60 and an area of 225. You need to know more details about the shape than just the perimeter.
The lengths of each of its sides.
Basically, because you need to know the volume of it.
I want to put a fence around my garden. My garden is 20' x 50'. In order to buy the correct amount of fencing, I would need to be able to find the perimeter (distance around) my garden.
If you know the perimeter, there is no need to find it again.
You need to know perimeter when you're fencing the yard. You need to know area when you're mowing it, seeding it, fertilizing it, buying it, or selling it.
You need to find perimeter when you buy a house, because then you know where your yard begins and ends.
As for example when constructing a round-about on a road you'll need to know its perimeter which is the circumference of a circle.
Laying turf then fencing it in
We would need to know the situation to be able to answer this question.
When you want to build a fence around your house, you need to know the perimeter.