Question 632841: A fence is to be on posts 8 meters apart around a rectangular lot that measures 40 meters
long and 16 meters wide. How many posts are needed, including the ones placed at each
corner, to fence the entire lot?
Found 2 solutions by Edwin McCravy, KMST:
Answer by Edwin McCravy(20055)   (Show Source):
Answer by KMST(5328)  (Show Source):
You can put this solution on YOUR website! The length and width are exact multiples of 8 meters,
 and  ,
so there is no problem placing the posts 8 meters apart.
You could figure our how many posts on each side, or calculate based on the whole perimeter.
USING THE PERIMETER:
The perimeter (in meters) is
That calculation is useful to calculate the amount of wire or other material that you need, to go with the posts.
That perimeter can be divided into 8-meter sections, getting
 such sections.
If we start at one corner, measure 8 meters, place a post there, and repeat, we place the first post at 8 meters from the starting point, the second at 16 meters, and so on, going around the lot, and we will end with the 14th post at
 meters from the start, which is the whole perimeter, meaning that we would be at the starting point.
If we keep going around, 8 meters further we would find the first post we installed, but we would not go further, because we know we are finished, and we would get back inside for a cool glass of lemonade, after all that hard work.
Here is what the fenced lot looks like now (as seen from our plane or helicopter).
If you are going to calculate post needed for each side, don't count the one at the end where you start each side (just like I did not install one at the first corner when going around the perimeter) because that post will be considered the last post of the other side. So you install posts at 8 and 16 meters from one end of each short side ( posts) and turn the corner installing posts at 8, 16, 24, ... 40 meters from that corner on the long side ( ) posts}}}.
You need 2 posts for each short side, and 5 for each long side.
The total is  posts any way you count them.
Drawing a picture and trying more than one way to solve a problem help you make sure that the answer makes sense.
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