derek planted a garden in the shape of a square 32 feet on each side. The garden has a stream on one side, but he plans so build a fence on the other three sides. If he puts a post every 8 feet, how many posts will he need?

the answer is 13

I don't get this

To find out how many posts Derek will need, we first need to calculate the perimeter of the garden. Since the garden is in the shape of a square, all four sides are equal in length.

The perimeter of a square can be calculated by multiplying the length of one side by 4. So, in this case, the perimeter of the square garden is 32 feet x 4 = 128 feet.

Now, since Derek plans to build a fence on three sides, he only needs to place posts along these three sides. The length of these three sides is equal to the perimeter of the garden, which we calculated to be 128 feet.

Given that Derek wants to place a post every 8 feet, we can also determine the number of posts he will need by dividing the total length by the distance between two posts.

So, 128 feet / 8 feet = 16 posts.

Therefore, Derek will need 16 posts to enclose his square garden.