For this problem, we just have to use the values we're given to calculate the approximate value of pi.
The formula presented is
[tex]\pi=Ar^{-2}[/tex]
When you have a negative exponent, we can use the following property
[tex]a^{-b}=\frac{1}{a^b}[/tex]
Using this property, our problem turns out to be
[tex]\pi=\frac{A}{r^2}[/tex]
Now, we just need to plug the given values on this equation
[tex]\pi=\frac{50.265}{4^2}=3.1415625\approx3.142[/tex]
The approximated value for pi is 3.142.
