# Project Help

• Feb 28th 2008, 03:29 PM
ClutchUSMC
Project Help
I need help with a precalc project. area, volume, inequalities, etc. i can email scans to anyone who thinks they can help. thanks.

heres the question
you are putting in a 20ftx30ft rectangular pool. your pool must be surrounded by a concrete sidewalk of uniform width and 3in thick.

write an expression in terms of x to represent the volume of concrete contained in the sidewalk. explain how you got your expression.
• Feb 28th 2008, 04:18 PM
Soroban
Hello, ClutchUSMC!

Quote:

You are putting in a 20ft x 30ft rectangular pool.
Your pool will be surrounded by a concrete sidewalk of uniform width and 3 inches thick.

Write an expression in terms of $\displaystyle x$ for the volume of concrete in the sidewalk.
Explain how you got your expression.

I assume that $\displaystyle x$ is the width of the sidewalk.
Code:

      : x : - 30  - : x :     - * - - - - - - - - * - -     x |                |  :     - |  * - - - - *  |  :     : |  |        |  |  :   20 |  |20      |  | 20+2x     : |  |    30  |  |  :     - |  * - - - - *  |  :     x |                |  :     - * - - - - - - - - * - -       : - -  30+2x  - - :

The total area is: .$\displaystyle (30+2x)(20+2x) \:=\:600 + 100x + 4x^2$ ft²

The pool area is: .$\displaystyle 30 \times 20 \:=\: 600$ ft²

The area of the sidewalk is: .$\displaystyle (600 + 100x + 4x^2) - 600 \:=\:100x + 4x^2$ ft²

The thickness of the sidewalk is: .$\displaystyle 3\text{ inches }=\:\frac{1}{4}\text{ ft}$

Therefore, the volume of the concrete is: .$\displaystyle V \;=\;\frac{1}{4}(100x + 4x^2) \;=\;25x + x^2$ ft³

• Feb 28th 2008, 05:07 PM
ClutchUSMC
the quoted price for finishing the concrete is
$.75 per square foot plus$.25 a linear foot measured along the outer perimeter. they have a minimum charge of \$500

write an expression for the number of square feet of concrete that will need to be finished. how much do you expect to pay for placing and finishing the concrete? why?
• Feb 28th 2008, 05:42 PM
ClutchUSMC
bump...