A carpenter's square is a ruler which looks like a right triangle. Being such, it has a long side and a short side. Assuming that the radius of each wheel is the size of the short side, we can use this to measure the mid point of the wheel. The mid point of the wheel is the optimal point where you can bore a hole.
We have,

To express periodic number calculated we use:

Hope this helps.
r3t40
The answer is 87. it was quite simple
2 years is the same as 24 months, so the equation would be:
685 = 24x + 85, where x is the monthly fee.
600 = 24x
600/24 = x
x = 25
The monthly fee is $25.
Your gonna divide 72 by 2 so therefore you get 36
So that equals to Nicole’s age