Radius of Diameter is 2.8 cm find Area of circle

Options

A. 6.21
B. 6.16
C. 59.8
D. 6.58

Answer

To find the area of a circle when the diameter is given, we first need to calculate the radius. The radius is half of the diameter.

### Step-by-Step Solution:

1. **Identify the Diameter**: The diameter of the circle is given as 2.8 cm.

2. **Calculate the Radius**:
\[ \text{Radius} = \frac{\text{Diameter}}{2} = \frac{2.8 \text{ cm}}{2} = 1.4 \text{ cm} \]

3. **Use the Area Formula**: The formula for the area \( A \) of a circle is:
\[ A = \pi r^2 \]
where \( r \) is the radius.

4. **Substitute the Radius into the Formula**:
\[ A = \pi (1.4 \text{ cm})^2 \]

5. **Calculate the Square of the Radius**:
\[ (1.4 \text{ cm})^2 = 1.96 \text{ cm}^2 \]

6. **Multiply by Pi**: Using \( \pi \approx 3.14 \):
\[ A = 3.14 \times 1.96 \text{ cm}^2 \]

7. **Perform the Multiplication**:
\[ A \approx 6.1584 \text{ cm}^2 \]

8. **Round the Answer**: Depending on the required precision, we can round it to two decimal places:
\[ A \approx 6.16 \text{ cm}^2 \]

### Final Answer:
The area of the circle is approximately \( 6.16 \text{ cm}^2 \).

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