Posted by
**MathMate** on
.

Sorry Anonymous that I deleted your post by mistake, but here's the answer to the question:

"there are four posts on each side of a square fenced-in are. How many posts are there in all?"

The corner posts are counted for both of the adjacent sides.

So the total number of posts

= 4 sides *(4-1) posts

= 12 posts.

Draw a little diagram to make sure you understand the situation.

*..*..*..*

. .

* *

. .

* *

. .

*..*..*..*