Question

modeling real life you want to install an in - ground basketball post. you dig a hole with the dimensions shown for the concrete. an 80 - pound bag of concrete mix yields 0.6 cubic feet. how many bags do you need to install the basketball post? you will need bags.

Explanation:

Step1: Calculate volume of the hole

The hole is a cylinder. The volume formula for a cylinder is $V=\pi r^{2}h$. The radius $r = \frac{1}{2}\times1\frac{1}{3}=\frac{2}{3}$ ft and height $h = 4$ ft. So $V=\pi\times(\frac{2}{3})^{2}\times4=\pi\times\frac{4}{9}\times4=\frac{16\pi}{9}\approx\frac{16\times 3.14}{9}\approx5.58$ cubic - feet.

Step2: Determine number of bags

Each bag yields 0.6 cubic - feet. Let the number of bags be $n$. Then $n=\frac{V}{0.6}$. Substituting $V\approx5.58$ cubic - feet, we get $n=\frac{5.58}{0.6}=9.3$. Since we can't buy a fraction of a bag, we need to round up to 10 bags.

Answer:

10