Given that radius is r= 4.1 inches.
let track the location of finger hole is at 12 o'clock.
i.e. the angle is 0 degree.
at 12 o'clock

Now when the finger hole changed by 45 degree:

Now convert 45 degree into radians:

So angle is such that:

Now calculate the measure of function in polar coordinates:

Taking measurement of function:

So the function become and the limit is:
