What is the area of a square having side of 21 cm ? 

Options

A. 112 cm
B. 321 cm
C. 441 cm
D. 121 cm

Answer

To find the area of a square with a side length of 21 cm, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the formula for the area of a square**:
The area \( A \) of a square is calculated using the formula:
\[ A = \text{side} \times \text{side} = \text{side}^2 \]

2. **Substitute the given side length into the formula**:
Here, the side length of the square is given as 21 cm. So, we substitute this value into the formula:
\[ A = 21 \, \text{cm} \times 21 \, \text{cm} \]

3. **Calculate the area**:
Now, we perform the multiplication:
\[ A = 21 \times 21 = 441 \, \text{cm}^2 \]

4. **State the final answer**:
Therefore, the area of the square with a side length of 21 cm is:
\[ \text{Area} = 441 \, \text{cm}^2 \]