How many cubic yards of concrete will need to be poured?
Mathematics

Tutor: None Selected  Time limit: 1 Day 
The concrete for a sidewalk is being poured outside the perimeter of a new subdivision, which is a 280 ft. by 720 ft. rectangle. The building code requires that the sidewalk be 5 feet wide and 8 inches deep. How many cubic yards of concrete will need to be poured? Explain your work step by step and why you took those steps. An average reader should be able to follow.
Thank you for the opportunity to help you with your question!
To best demonstrate this problem it is easier to first draw a rectangle. Label the left of the rectangle as 280 ft, and the top of the rectangle as 720 ft.
Next, you need to add five feet to the existing rectangle on all sides. So, draw another rectangle slightly bigger than the first triangle.
Note, that this changes the length and wide of the original rectangle. It adds an extra five to both sides, and an extra five to top and bottom.
Therefore you take the original 280ft +10ft=290 ft, and the original 720ft+10ft=730ft.
To calculate cubic yards : length in yards x width in yards x height in yards.
Once you convert each to yards: the cubic yards for the width is 2.95 cubic yards x 2 (since you have two widths)= 5.9 cubic yards
The cubic yards for the length is 7.43 cubic yards x 2 (since you have two lengths) = 14.86 cubic yards.
Add these two: 5.9 cubic yards + 14.86 cubic yards= 20.76 cubic yards in total.
* I made some calculator mistakes* I am so sorry
Ft to yard conversion=
1ft= .3333333 yards
290 yards x .3333333= 96.7 yards
5 ft x .3333333= 1.67 yards
8 in = .67 ft
.67 ft x .3333333= .22 yards
76.7 yard x 1.67 yard x .22 yard= 35.52758 cubic yards x 2 = 71.05 cubic yards
730 ft x .3333333= 243.33 yards
243.333 x 1.67 yard x .22 yard= 89.4 cubic yards x 2= 178.8 cubic yards
243.33+178.8= 422.13 cubic yards
433 cubic yards in total.
* Sorry, typing error. 423 cubic yards in total.
I feel really bad, and I understand if you want to give me a bad review. I realized I made another typo and therefore error. To redeem myself, and hope to give you the final answer by a picture. Please look at the attachment, and let me know if you have any questions at all. 20150829_214040.jpg
Hey, no problem! No need to feel bad, everyone makes mistakes. It's perfectly fine, considering you took your own time to help me with my question. No biggie. Thank you so much for the help!
Thank you for understanding, and I hope you enjoy the rest of your day. You are very welcome for the help.
One question, why multiply by 1.67, when 8 inches is only .67 ft?
Just in case you do not see the chat for a while. I initially thought I was wrong again, when I was not.
1.67 yard is the measurement for the five feet.
Ohhhhhhhhhhh!! I get it now... Haha, sorry :D. And thank you!
It is absolutely no problem, I am glad I could clarify.
Looking at this problem again, I believe there is a mistake. I forgot to account for the overlapping parts of the rectangle. Therefore the area is a little bit higher, but it is an easy mistake to fix. Let me draw you a picture of what I mean.
Yea, I was wondering that, too, after multiplying during the conversions again
Wait... How?
Nevermind
Wait, so while doing the math for the width, I don't need to do 290 ft x .33333? Because you used 280 ft x .33333, and then used that answer to move on to multiplying it by 1.67 and then by .22. So I can get rid of the 290 ft x .33333?
Secure Information
Content will be erased after question is completed.