SOLUTION: A photograph measures 20 cm by 16 cm. A strip of constant width is to be cut off the top and one side of the photo, so the area is reduced to 60% of the area of the original photo.

Algebra ->  Customizable Word Problem Solvers  -> Geometry -> SOLUTION: A photograph measures 20 cm by 16 cm. A strip of constant width is to be cut off the top and one side of the photo, so the area is reduced to 60% of the area of the original photo.      Log On

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Question 260314: A photograph measures 20 cm by 16 cm. A strip of constant width is to be cut off the top and one side of the photo, so the area is reduced to 60% of the area of the original photo. Find the width of the cut.
Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
The original area is 20x 16 = 320
The new area is to be 320*.60 = 192
we get
%2820-x%29%2816-x%29+=+192
By foil, we get
x%5E2+-+36x+%2B+320+=+192
setting = 0 we get
x%5E2+-+36x+%2B128=+0
%28x-32%29%28x-4%29=0
x = 32 cm
or
x = 4 cm.
x = 4 cm is our answer.