Question 173875
Let x=Width
Let 2x=Length
Let x+84=Perimeter
x+84=x+x+2x+2x
combine:
x+84=6x
subract the X on left side to further solve
84=5x
divide each side by 5 to isolate
16.8=x

To prove
2(16.8)+2(33.6)=100.8
then if you subtract 84 from it, it equals the width

So the dimensions are 16.8x33.6