Finding an arc length requires knowing a bit about the geometry of a circle. Since the arc is a portion of the circumference, if you know what portion of 360 degrees the arc’s central angle is, you can easily find the length of the arc.
Answer:
You shoud invest $0.204, it is an small amount each month.
The formula to calculate the monthly saving is
with PP: periodic payments, A: amount desired, n: number of payments in one year, Y: number of years.
In this case A = 88, n= 12 (the payments are monthly), Y=18, APR=7%.
Replacing in the formula you obtain that