That number is impossible to round... It is probably already been rounded to the Highest form.
400,000 has not other numbers to round up or down (Unless you say 4 but then it would stay as it is)
I believe it would be 144 :)
The formula for circumference is 2

r, where r is equal to radius.
It states to use 3.142 for pi
It also provides you with the diameter, not the radius, so you have to divide it by two to get 4.5
2*3.142*4.5= approximately 28.278 or 28.3