1. The tree trunk has the shape of a cylinder
2. The volume of a cylinder is base area*height.
3. Volume= [tex] \pi r^{2} *h[/tex] . We have the height, and we need the radius, which can be found using the circumference formula.
4. Circumference = [tex]2 \pi r[/tex]
[tex]4.5=2 \pi r[/tex]
[tex]r=\frac{4.5}{2 \pi } [/tex] (feet)
5. [tex]V=\pi r^{2} *h= \pi (\frac{4.5}{2 \pi })^{2}*12= \pi \frac{20.25}{ 4 \pi ^{2}}*12= \frac{20.25*3}{\pi} [/tex]
with [tex] \pi [/tex] approximately equal to 3.14,
[tex]V= \frac{20.25*3}{3.14}=19.35[/tex] (feet cubed)
