Use the image to answer the question.

A cone is placed inside a cylinder. The apex of the cone touching the center of the top circle of the cylinder is highlighted with a dot. The cone with its base is drawn in dashed lines. The base of the cone is common with the base of the cylinder.

A sculptor is creating a design by carving a cone out of a cylinder. The cone and cylinder share the same radius and height. If the volume remaining is 144 in.3
, what was the volume of the original cylinder?(1 point)
Responses

288 in.3
288 in. cubed

216 in.3
216 in. cubed

192 in.3
192 in. cubed

180 in.3

1 answer

To find the volume of the original cylinder, we first need to understand the relationship between the cylinder volume and the cone volume.

The volume \( V \) of a cylinder is given by the formula:

\[ V_{cylinder} = \pi r^2 h \]

where \( r \) is the radius and \( h \) is the height of the cylinder.

The volume \( V \) of a cone is given by the formula:

\[ V_{cone} = \frac{1}{3} \pi r^2 h \]

Given that the cone and the cylinder share the same radius and height, the volume relationship can be simplified. The volume of the remaining material after carving out the cone from the cylinder is:

\[ V_{remaining} = V_{cylinder} - V_{cone} \]

Substituting the formulas for the volumes, we have:

\[ V_{remaining} = \pi r^2 h - \frac{1}{3} \pi r^2 h \]

Factoring out \( \pi r^2 h \):

\[ V_{remaining} = \pi r^2 h \left(1 - \frac{1}{3}\right) = \pi r^2 h \left(\frac{2}{3}\right) \]

We know that the remaining volume is 144 in³:

\[ \frac{2}{3} \pi r^2 h = 144 \]

To find the volume of the cylinder, we can express it in terms of \( V_{remaining} \):

\[ V_{cylinder} = V_{remaining} + V_{cone} = 144 + \frac{1}{3} \cdot V_{cylinder} \]

Let \( V_{cylinder} = V \). Thus:

\[ V = 144 + \frac{1}{3} V \]

Now, multiplying through by 3 to eliminate the fraction:

\[ 3V = 432 + V \]

Rearranging gives:

\[ 3V - V = 432 \]

\[ 2V = 432 \]

Now, dividing both sides by 2:

\[ V = 216 \]

Thus, the volume of the original cylinder is 216 in³ (216 in. cubed).

The correct response is: 216 in.3 or 216 in. cubed.