SOLUTION: What formula would i use for this problem? A rectangular picture frame of uniform width has outer dimensions of 12 by 18 inches. Describe the process to decide how wide (to the ne
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Question 348036: What formula would i use for this problem? A rectangular picture frame of uniform width has outer dimensions of 12 by 18 inches. Describe the process to decide how wide (to the nearest tenthof an inch) must the frame be to display an area of 140 sqaure inches?
Thankyou Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website! let the width be x
the outer dimensions are
length =18 in
width = 12 in
Area = 216 sq.in
..
the length of display will be 18-2x
the width of display will be 12-2x
(18-2x)(12-2x)=140
216-36x-24x+4x^2=140
4x^2-60x+216-140=0
4x^2-60x+76=0
divide by 4
x^2-15x+19=0
..
solve the equation using quadratic formula
a=1b=-15c=19
x= width = 1.396 OR 1.4 inches.
