# What's the formula to solve this one? Thanks!

#### jaytheseer

##### New member
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?

#### MarkFL

Staff member
I would place the corner posts first, so that is 4 posts. Now for the two shorter sides, how many additional posts are needed? How about for the two longer sides?

#### jaytheseer

##### New member
Hmmmm.... 1 additional post on each of the shorter sides and 3 additional post on each of the longer sides?
So it will be a total of 12 posts including the 4 corner posts. Is that correct?

#### MarkFL

Staff member
Hmmmm.... 1 additional post on each of the shorter sides and 3 additional post on each of the longer sides?
So it will be a total of 12 posts including the 4 corner posts. Is that correct?
No, that's not correct.

If you add 3 additional posts on each longer side, how many spaces are then created on these sides?

#### jaytheseer

##### New member
8 spaces on two longer sides...

Last edited:

#### MarkFL

Staff member
4 spaces...
Correct, and so if these longer sides are 40 m in length, what would the length of these 4 spaces be, assuming they are all equal?

#### soroban

##### Well-known member
Hello, jaytheseer!

Why are the corner posts given special mention?
Is there someone who would forget about them?

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?

While you are waiting for The Fence Post Formula,
. . I would make a sketch . . .

Code:
      o---o---o---o---o---o
|                   |
o                   o
|                   |
o---o---o---o---o---o
. . . and count them.