Question

ylinders, cone Justin uses the mold picture cement column posts to use a height of the Cylinder = 18 in To make a post, Justin completel wet cement How much wet cement, in cubic inche make 4 posts? dus 3 in Formula Sheet

Answer 1

`\begin{gathered} \text{Volume for 1 post= }Volume\text{ of cone + Volume of Cylinder} \\ Volume\text{ of cone= }(\pi r^2h)/(3) \\ r=\text{ }3in \\ h_(cone)=3in \\ Volume\text{ of cone= }(\pi(3)^2(3))/(3)=(\pi(9)(3))/(3)=(27\pi)/(3)=9\pi \\ Volume\text{ of cone is }9\pi in^3 \\ \text{Volume of Cylinder=}\pi r^2h \\ r=\text{ }3in \\ h_(CylInder)=18\text{ in} \\ \text{Volume of Cylinder=}\pi(3)^2\cdot(18) \\ \text{Volume of Cylinder=}\pi(3)^2\cdot(18)=162\pi \\ Volume\text{ of Cylinder is 162}\pi in^3 \\ \\ \text{Volume for 1 post= }9\pi in^3\text{ + 162}\pi in^3 \\ \text{Volume for 1 post= }171\pi in^3 \\ \text{Volume for 4 post=4}\cdot(171\pi in^3) \\ \text{Volume for 4 post=684}\pi in^3 \\ \text{Volume for 4 post=2,148.85}in^3 \\ \text{Justin n}eeds\text{ 2,148.85}in^3of\text{ wet cement to }make\text{ 4 posts} \end{gathered}`