# How do you come to this result, my final amount comes to 11701.2728 cm3 instead? Where am I going wrong? Thanks

### 2 Answers | Add Yours

**To determine the capacity of the beer jug, we'll have to compute the volume of the conical frustum:**

** , where r1 is the radius of top diameter and r2 is the radius of bottom diameter.**

**We'll calculate the radii r1 and r2:**

**r1 = 14.6/2**

**r1 = 7.3 cm**

**r2 = 12/2**

**r2 = 6 cm**

**The height of the conical frustum is: h = 28 cm.**

**Now, we'll calculate the volume:**

**Now, we'll convert cube centimeters in liters.**

**We know that 1 cubic centimeter = 0.001 liters, therefore the liter capacity of the beer jug is of 1.242173 liters.**

The original answer of 1.242173 liters appears to contain an arithmetic mistake.

`(28*pi*(7.3^2+6^2+7.6*6))/(3)=(28*pi*133.09)/(3)`

If you do not round pi you will get 11707.2078555/3=3902.4 cm^3

If you round pi to 3.14 you will get 11701.2728/3= 3900.4 cm^3

so the answer should be approximately 3.9 liters.

Here is the link to the original equation.

http://www.enotes.com/math/q-and-a/how-do-work-out-litre-capacity-beer-jug-top-276310

Thanks!