charlie is designing an 80 ft by 120ft rectangular fence. he wants to put posts 10ft apart along one of the 120 ft sides. the posts will be 8ft apart along the other three sides of the fence. how many posts does charlie need?
To find the number of posts Charlie needs, we first need to calculate the length of the 120 ft side that the posts will be placed along.
The posts will be placed 10 ft apart, so the number of spaces between the posts is equal to the total length divided by the spacing: 120 ft ÷ 10 ft = 12 spaces.
Since there are 12 spaces, there will be 12 + 1 posts along the 120 ft side. This is because we need to include the beginning and the end of the fence.
So, Charlie needs 12 + 1 = 13 posts along the 120 ft side.
Now let's calculate the number of posts along the other three sides of the fence. The posts will be placed 8 ft apart, so the spacing is different from the previous side.
For each side with a length of 80 ft, we need to divide it by the spacing and add 1 to include the ending post.
So, the number of posts along each of the 80 ft sides is: 80 ft ÷ 8 ft + 1 = 10 + 1 = 11 posts.
Since there are three 80 ft sides, Charlie needs a total of 11 x 3 = 33 posts along those sides.
Adding up the posts from each side, Charlie will need 13 + 33 = 46 posts in total.
Therefore, Charlie needs 46 posts for the entire rectangular fence.