First we need to find the radius of the cylindrical tree trunk if the circumference C=4 feet: C=2rπ, r=4/(2π)=2/π. Now we find the volume V: V=r^2π*h, where h=20 feet is the height. So we input the numbers: V=(2/π)^2*π*20=(4/π²)*π*20. π in the nominator and the denominator cancel out: V=(4/π)*40=80/π. The volume of the cylindrical tree trunk is V=80/π feet^3
I think they should keep it around, even if it might not be the most efficient strategy. After all, what if you need to solve a problem using multiple strategies?
Since the common difference is 6, we can assume that the sequence is arithmetic, with rule
T(n)=6n+5 where T(1)=11
T(9)=6(9)+5=59
This is 1.446 * 10^9 / 6.025 * 10^4 = 0.24 * 10^5 = 2.4 * 10^4 Answer
