SOLUTION: A rectangular garden is to be surrounded by a walkway of constant width. The garden's dimensions are 30ft by 40ft. The total area, garden plus walkway, is to be 1800ft^2. What mu

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Question 125858: A rectangular garden is to be surrounded by a walkway of constant width. The garden's dimensions are 30ft by 40ft. The total area, garden plus walkway, is to be 1800ft^2. What must be the width of the walkway to the nearest thousandth?
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
(30+2x)(40+2x)=1,800
1,200+80x+60x+4x^2=1,800
4x^2+140x+1,200-1,800=0
4x^2+120x-600=0
4(x^2+30x-150)=0
using the quadratic equation:x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ we get:
x=(-30+-sqrt[30^2-4*1*-150])/2*1
x=(-30+-sqrt[900+600])/2
x=(-30+-sqrt1500)/2
x=(-30+-38.73)/2
x=(-30+38.73)/2
x=8.73/2
x=4.365 ft is the width of the walkway.