PLEASE tell me if I am way off. The answer I got for this one is 3.5 ft.
A parking lot measures 100 by 130 feet. A sidewalk of uniform width is to completely surround the lot. If the sidewalk covers 1659 sq ft. how wide can the sidewalk be?
you have rectangle 100x130
Originally Posted by sallyann
the sidewalk plus the parking lot equals: (100+2s)x(130+2s)
the area is therefore: (100+2s)x(130+2s)=13000+260s+200s+4s^2=4s^2+460s+1 3000
now subtract the original rectangle area (100x130=13000) from the sidewalk+parking lot area to get: 4s^2+460s
that expression gives the area of the sidewalk for width "s"
now solve for: 4s^2+460s=1659
which comes out to: s=3.5
so you got it right :)