The perimeter of the square is given by:

Where,
x: square side.
Substituting values we have:

Rewriting the perimeter of the square we have:

Finally, dividing both values:

Answer:
the perimeter of the square is:

We'll be assuming this is with simple interest.
now, a year has 12 months, thus in 18 months there are 18/12 years.

Answer:
41.33
Step-by-step explanation:
you divide 124 by 3
"color the piece according to your color chart." Do you have that? If you don't, I wouldn't worry, you still did all the work and got all the answers, so your teacher should be fine with it.