Question 913944
The equation for the perimeter of a rectangle is {{{2l+2w=P}}}. We already know the perimeter and the length, so let's plug those into the equation. We get:

{{{2*3.91+2w=9.1}}}
{{{7.82+2w=9.1}}}

Subtract 7.82 from both sides.

{{{2w=1.28}}}

Divide 2 from both sides.

{{{w=0.64}}}

The width is 0.64 inches. Hope I helped!