Need some help figuring out something.. Im supposed to calculate

Customer Question

Need some help figuring out something.. I'm supposed to calculate the volume of clay to be used to fill up this racetrack [shown here: http://i50.tinypic.com/2h2qc92.png] with 70cm of clay. rWidth is 300m, rLength is 400m, tWidth is 20m.

What I'm asking for is NOT an answer, but rather, the formula I'd need to use to find the volume. Any help would be appreciated, thank you. I've been at this for a while with no success.

Hi. Thanks for your question! It's an interesting problem. Here's how I'd solve it.

Start by calculating the area of the racetrack.

The racetrack is made up of two "strips" (the straight part of the track, along the top and bottom), plus a hollow circle. The circle is cut in half and stuck onto the two ends of the track.

So, first you calculate the area of the strips. Each strip has area tWidth * rLength, but you have to multiply that by two (because there are two of them) to get the Total Strip Area.

Now you need the area of the hollow circle. To get that, you first calculate the area of the outer circle. That's pi * r^2, where r is the radius of the circle.

The radius of the outer circle is half of rWidth + tWidth (basically, half the length of the dotted line in your diagram).

Then calculate the area of the inner circle. The formula is the same, but now the radius is half of rWidth only.

Area of the circular part of the track is Outer Circle Area - Inner Circle Area.

Now add the area of the circular part of the track to theTotal Strip Area and you've got the total racetrack area.

Once you have the area of the racetrack, calculate the volume by multiplying the area in meters by 0.7m (70cm) to get the area in m^3.

Let me know if you run into any trouble and I'd be happy to walk you through the steps in more detail. I think the hardest part of this is realizing that the two curved ends of the track make up a circle, and also how to find the radius of both the inner and outer circles.

Hi Susan, I have a problem. When I ran the numbers I got 18017.25605, but the given answer says 25274.335088. Did I do something wrong or is there an error in the answer given to me? Thanks.

THIS ANSWER IS LOCKED! You can view this answer by clicking here to Register or Login and paying $3. If you've already paid for this answer, simply Login.

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.

JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.

Web sites like justanswer.com/legal ...leave nothing to chance.

Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.

Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.

I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C.Freshfield, Liverpool, UK

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. RobinElkton, Maryland

He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here.DianeDallas, TX