If a cut section of cylindrical tree trunk is 20 feet long and 4 feet around, what is the volume of wood in the section of the tree trunk? (in terms of π)
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
