It costs $ 3.4 to fill the hot tub
<h3><u>Solution:</u></h3>
Given that, You are putting a rectangular hot tub on your back porch
The rectangular hot tub is of shape cuboid
<em><u>The volume of cuboid is given as:</u></em>
![\text{Volume of cuboid } = length \times width \times height](https://tex.z-dn.net/?f=%5Ctext%7BVolume%20of%20cuboid%20%7D%20%3D%20length%20%5Ctimes%20width%20%5Ctimes%20height)
It is 6 feet long, 5 feet wide, and 3 feet deep
Therefore,
length = 6 feet
width = 5 feet
height = 3 feet
<em><u>Thus volume of rectangular hot tub is:</u></em>
![volume = 6 \times 5 \times 3 = 90](https://tex.z-dn.net/?f=volume%20%3D%206%20%5Ctimes%205%20%5Ctimes%203%20%3D%2090)
Thus volume of rectangular tub is ![90 ft^3](https://tex.z-dn.net/?f=90%20ft%5E3)
Convert feet to gallons
We know that,
1 cubic feet = 7.48052 gallon
Therefore,
90 cubic feet = 7.48052 x 90 = 673.247
Thus gallons of water tub can hold is 673.247 gallons
Given that it costs $ 5 per 1000 gallons
1000 gallons = $ 5
Therefore,
1 gallons = $ ![\frac{5}{1000}](https://tex.z-dn.net/?f=%5Cfrac%7B5%7D%7B1000%7D)
<em><u>Find for 673.247 gallons</u></em>
673.247 gallons = ![\frac{5}{1000} \times 673.247 = 3.366235 \approx 3.4](https://tex.z-dn.net/?f=%5Cfrac%7B5%7D%7B1000%7D%20%5Ctimes%20673.247%20%3D%203.366235%20%5Capprox%203.4)
Thus it costs $ 3.4 to fill the hot tub