Question 246096
Is x the diameter of the silo or the radius?
if x is the radius then the silo takes up pi x^2
if x is the diameter then the silo takes up pi *(x/2)^2
We have 23*17=391 sq meters for the corral without the silo
A=391-pi * x^2 
or 
A=391-pi *(x/2)^2