MA109 Written Project - Spring 2018

Your submission must be turned in on canvas by 5pm on Friday, April 20, 2018. This project is worth 20 points (4% of your final grade) in the calculation of your final grade. One point (0.2% of your final grade) is deducted for every 6 hours the project is late.

This page will give the context of the problem that you will analyze, then six prompts for your response, and finally a rubric describing how your responses will be evaluated.

Pies are round

Imagine you have graduated and have just gotten a job in a fictionalized version of Casey County, KY, home of the world famous Apple Festival. You and your business partner have been put in charge of getting ingredients for the 10 foot apple pie, but you're under pressure to reduce spending.

Your business partner presents the following plan to save over $600!

A standard 9 inch pie requires about 2 2/3 pounds of apples. Since 9 inches times 12 is 9 feet, 12 times 2 2/3 (which is 32) pounds should be enough for a 9 foot pie. 9 feet isn't quite enough, but 13 times 9 inches is nearly 10 feet, so 13 times 2 2/3 (which is 34 2/3) pounds should be nearly enough for the 10 foot pie. At around $1.40 per pound of apples, that is about $48.50 in apples. Round up to $50 to be safe.

Your business partner is pretty excited, because last year they spent over $650 on apples, so you're already saving a ton of money!

Before you brag about saving $600, maybe you should check your business partner's math.

Your responses

  1. What is wrong with the following argument?

    Last year's apples were $1.50 per pound, so that's why it was $600 more expensive.

    Make sure to explain (quantitatively) how much of a difference the $1.40 versus $1.50 price will affect the cost of 35 pounds of apples.

  2. What is wrong with the following argument?

    You don't multiply 9 inches by 13 to get 10 feet. That only gives 9 foot, 9 inches. The missing 3 inches is why it is going to be $600 more expensive.

    Make sure to explain which number you should multiply 9 inches by to get 10 feet. Make sure to explain (quantitatively) how much of a difference in total price using 13 versus using the correct number makes. How many pounds and how much would it cost using this other number?

  3. Find an authoritative source for how changing the size of a pie affects the amount of ingredients needed.

  4. What is the name of the mathematical shape that approximates a pie? What is the mathematical name of the size of the pie as measured by "9 inches"? What is the mathematical name most closely related to the size of the pie as measured by "2 2/3 pounds"?

  5. Calculate the correct amount of apples needed for pies of various sizes: 1ft, 2ft, …, 11ft. Make sure to give decimal answers as well as a formula.

  6. Make a table showing how much MORE each foot costs. Give a simple formula, though you don't need to prove your formula is always correct (but it should work for all the numbers in your table!).

The rubric

Your submission must be turned in on canvas by 5pm on Friday, April 20, 2018. This project is worth 20 points (4% of your final grade) in the calculation of your final grade. One point (0.2% of your final grade) is deducted for every 6 hours the project is late.

Your response to #1 will be graded on the clarity of your critique and its mathematical correctness. It should clearly identify the problem. It may be combined with your answer to #2, which is graded similarly. You don't need to include a full solution for why $650 is much closer to the correct price than $50, just explain why the arguments given don't come close to $650.

Your response to #3 and #4 will be graded on the appropriateness of your source, the clarity of your citation, and the clarity of your description of how the mathematical terms relate to pie.

Your response to #5 and #6 will be graded on the clarity of your presentation and its mathematical correctness. You'll need to give a mathematical formula, and make a table.