To find the volume of a cylinder, you can use the formula:
\[ V = \pi r^2 h \]
where:
- \( V \) is the volume,
- \( r \) is the radius of the base of the cylinder,
- \( h \) is the height of the cylinder.
Given that the diameter of the cylinder is 4 cm, the radius \( r \) will be half of the diameter:
\[ r = \frac{4 \text{ cm}}{2} = 2 \text{ cm} \]
The height \( h \) of the cylinder is given as 9 cm.
Now, substitute the values into the volume formula:
\[ V = 3.14 \times (2 \text{ cm})^2 \times 9 \text{ cm} \]
Calculate \( (2 \text{ cm})^2 \):
\[ (2 \text{ cm})^2 = 4 \text{ cm}^2 \]
Now substitute that into the formula:
\[ V = 3.14 \times 4 \text{ cm}^2 \times 9 \text{ cm} \]
Calculate \( 4 \times 9 \):
\[ 4 \times 9 = 36 \]
Now, substitute back:
\[ V = 3.14 \times 36 \text{ cm}^3 \]
Now, calculate \( 3.14 \times 36 \):
\[ V \approx 113.04 \text{ cm}^3 \]
Therefore, the approximate volume of the cylinder is \( 113.04 \text{ cm}^3 \).