Answer
Width = 6.5471cm
Length = 11.5471cm
Work Step by Step
$12*7*3=252$
252 * 0.9 = new volume = 226.8
The width and length must decrease by the same amount; we can call this length x. We can then now create this equation:
$3(12-x)(7-x)=226.8$
We can now solve this equation to get the value for x
When we expand it out we get:
$5x^2-95x+42=0$
We can use the quadratic formula, which is:
$\frac{-b+-\sqrt( b^2-4ac)}{2a}$
Where a= 5
b=-95
c=42
We then get a value for x as 18.547 and 0.4529
18.... is greater then 12 therefore we can reject this value for x.
We can now subtract 0.4529 from 12 and 7 to give us the width and length.
