The Golden Ratio is the positive solution to x=1/(1+x), x2+x-1=0, x=(-1+√(1+4))/2=0.618 approx.
That is: 0.618=1/1.618 and 1.618=1/0.618. Applying this ratio to width 7in we get 4.3262in approx. Or applying the ratio to get a length we get 11.3262in.