Hello!
To find how much shelves we cut, we need to divide 9 feet by 3/7 feet. When dividing by fractions, it is like multiplying its reciprocal.
This means that the reciprocal of 3/7 is 7/3.
[tex]9 / \frac{3}{7} = \frac{9}{1} * \frac{7}{3} = \frac{63}{3} = 21[/tex]
Therefore, if each shelf is 3/7 feet in length, then there are 21 shelves.
