20. Coefficients are always the number. The letters are variables
Personally,you may need to declassify the form of details of function f,
A=(1/2)(r^2)(sin[360/n])(n)
A=(1/2)(8^2)(sin[360/15])(15)
A=(1/2)(64)(sin[24°])(15)
A=(1/2)(64)(0.40673664)(15)
A= 195.2335872
The data value 110 would be considered an outlier, all of the numbers are within the range 20 to 40.