Let be the dimensions of the rectangle. We know the equations for both area and perimeter:
So, we have the following system:
From the second equation, we can deduce
Plug this in the first equation to get
Refactor as
And solve with the usual quadratic formula to get
Both solutions are feasible, because they're both positive.
If we chose the positive solution, we have
If we choose the negative solution, we have
So, we're just swapping the role of and . The two dimensions of the rectangle are and
Penatgon
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hi
here is the trick
take new value , substract first value, then divise by first value and multiply by 100
so new value = 2.10
first value = 2.45
2.10 -2.45 = - 0.35
-0.35 / 2.45 = - 0.1428
-0.1428 * 100 = - 14.28 %
So decrease is of 14.3 % rounded to the nearest tenth.