The diameter of a cylinder is 14 cm and its height is 20 cm. Then curved surface of cylinder wil be:

Options

A. `440cm^2`
B. `220cm^2`
C. `880cm^2`
D. `1760cm^2`

Answer

To find the curved surface area of a cylinder, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the given values**:
- Diameter of the cylinder = 14 cm
- Height of the cylinder (h) = 20 cm

2. **Calculate the radius of the cylinder**:
- The radius (r) is half of the diameter.
\[ r = \frac{\text{Diameter}}{2} = \frac{14 \text{ cm}}{2} = 7 \text{ cm} \]

3. **Use the formula for the curved surface area of a cylinder**:
- The formula for the curved surface area (CSA) is:
\[ \text{CSA} = 2 \pi r h \]

4. **Substitute the values into the formula**:
- Now substitute \( r = 7 \text{ cm} \) and \( h = 20 \text{ cm} \) into the formula:
\[ \text{CSA} = 2 \pi (7 \text{ cm}) (20 \text{ cm}) \]

5. **Calculate the numerical value**:
- First, calculate \( 2 \times 7 \times 20 \):
\[ 2 \times 7 = 14 \]
\[ 14 \times 20 = 280 \]
- Now, multiply by \( \pi \) (approximately \( 3.14 \)):
\[ \text{CSA} \approx 280 \times 3.14 = 879.2 \text{ cm}^2 \]

6. **Final result**:
- The curved surface area of the cylinder is approximately \( 879.2 \text{ cm}^2 \).