Answer :
So,
Melissa's rope is 84ft. long.
Each piece must be 7ft. long.
We divide the length of the rope by the required length of each piece.
Now we have a fraction: 84/7
Prime Factorization
Prime factored form of 84: 2*2*3*7
Prime factored form of 7: 7
Cross out 7's
2*2*3/1 or 12/1 or 12
Melissa can make 12 ropes.
Melissa's rope is 84ft. long.
Each piece must be 7ft. long.
We divide the length of the rope by the required length of each piece.
Now we have a fraction: 84/7
Prime Factorization
Prime factored form of 84: 2*2*3*7
Prime factored form of 7: 7
Cross out 7's
2*2*3/1 or 12/1 or 12
Melissa can make 12 ropes.