Posted by Amanda on Saturday, October 27, 2007 at 1:14am.
How can I write a polynomial equation for this problem and draw a labeled diagram?
A developer wants to build homes on a rectangular plot of land 4 kilometers long and 3 kilometers wide. In this part of the city, regulations require a greenbelt of uniform width along two adjacent sides. The greenbelt must be 10 times the area of the development. Find the width of the greenbelt.

Precalculus/Trigonometry  drwls, Saturday, October 27, 2007 at 2:25am
Let the greenbelt width be x. The developed area is (5x)*(4x). The greenbelt area is 5x + (4x)x = 9x  x^2
The requirement is
9x  x^2 = 10 *(x^2 9x +20)
11 x^2 99 x +200 = 0
x^2  9x + 200/11 = 0
The labeled diagram is one rectangle nested inside a larger triangle with one pair of corners aligned, and a gap of x along the two perpendicular opposite sides