Question 1103616: A photo measures 10cm by 8cm. The photo is cropped by cutting a strip of a constant width of the top and one side of the photo. If the new area of the new photo is reduced to 62.5% of the original area, find the width of the cut and the new dimensions of the cropped photo.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! Area is 80 cm^2=10 x 8
Need to reduce it to 5/8 (62.5%) of original area, which is 50 cm^2.
The amount removed is x and that is 2x from each the 10 and the 8.
(10-2x)^2(8-2x)^2=50
80-36x+4x^2=50
4x^2-36x+30=0
2x^2-18x+15=0
x=(1/4)(18+/-sqrt(324-120))
x=(1/4)(18+ sqrt (204))=8.07, doesn't make sense. Other root is
x=(1/4)(18-sqrt (204))=0.93 cm one ANSWER
The new dimensions are 10-1.86=8.14 cm x 8-1.86=6.14 cm other ANSWER
That product is 49.98 cm^2, close enough with rounding error.
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