Question

a rectangle frame has a length of 3 1/8 feet and an area of 2 3/4 square feet. what is the width w, in feet, of the frame?

Answer 1

I think you have the area and length swapped if that's true, continue:

3.125 divided by 2.75 is 1.13(continues on with 36 repeating)
this means that 1.13 Feet is the width because you basically take the equation backwards:
L*W=A
therefore,
A/L=W
or
A/W=L

Answer 2

A = L * W
2 3/4 = 3 1/8 * W
Change to improper fractions.
11/4 = 25/8 * W
Multiply both sides by the reciprocal of 25/8 (8/25) to clear the fraction with the W.
(8/25)(11/4) = W
88/100 = W
22/25 = W OR 0.88ft