Basically, it can't be done.
Square feet is a measure of area, such as the area of a floor.
Linear feet is a measure of length, such as the length of one side of a floor.
There are some problems, such as how many linear feet of a floor covering does it take to cover the floor, can be answered if the width of each of the floor sections is known. If you have this type of problem, post back with more information.
Basically, it can't be done.
Square feet is a measure of area, such as the area of a floor.
Linear feet is a measure of length, such as the length of one side of a floor.
There are some problems, such as how many linear feet of a floor covering does it take to cover the floor, can be answered if the width of each of the floor sections is known. If you have this type of problem, post back with more information.