Let's break down the problem step by step to clarify the calculations and explain the reasoning behind each step.
Given Information:
- Volume of Ice Cream in Cone = 4 in³
- Height of Cone = 2r (meaning height = double the radius)
- Volume of Cone Formula: \[ V = \frac{1}{3} \pi r^2 h \] Substituting the height in this case, we have: \[ V = \frac{1}{3} \pi r^2 (2r) = \frac{2}{3} \pi r^3 \]
From the problem statement:
- The volume of the cone is given as 4 cubic inches: \[ \frac{2}{3} \pi r^3 = 4 \]
Solve for Radius:
- Rearranging for \( r^3 \): \[ 2 \pi r^3 = 12 ; \text{(multiplying both sides by 3)} \] \[ \pi r^3 = 6 \] \[ r^3 = \frac{6}{\pi} \]
Volume of Hemisphere:
Next, we add the volume of the perfect hemisphere on top of the cone. The volume \( V \) of a hemisphere is given by the formula: \[ V = \frac{2}{3} \pi r^3 \]
Total Volume of Ice Cream:
- The total volume of ice cream consists of the volume inside the cone and the volume of the hemisphere: \[ \text{Total Volume} = \text{Volume of Cone} + \text{Volume of Hemisphere} \]
Using the previous calculations, we can substitute \( \frac{2}{3} \pi r^3 \) for the cone and \( \frac{2}{3} \pi r^3 \) for the hemisphere: \[ \text{Total Volume} = \frac{2}{3} \pi r^3 + \frac{2}{3} \pi r^3 = \frac{4}{3} \pi r^3 \]
Substitute \( r^3 \):
From our earlier calculation: \[ r^3 = \frac{6}{\pi} \]
Substitute this into the total volume formula: \[ \text{Total Volume} = \frac{4}{3} \pi \left(\frac{6}{\pi}\right) \] \[ = \frac{4 \cdot 6}{3} = 8 \text{ in³} \]
Conclusion:
The total volume of ice cream in and on top of the cone is \( 8 \text{ in}^3 \).
This step-by-step breakdown explains how we derived the volumes and arrived at the final total volume of ice cream.