What is the area of a circle with a diameter of 10 cm? (Use π ≈ 3.14)

What is the area of a circle with a diameter of 10 cm? (Use π ≈ 3.14)

• A. 31.4 cm²
• B. 78.5 cm²
• C. 25 cm²
• D. 50 cm²

Answer: (B)

To find the area of a circle, you can use the formula: \[ \text{Area} = \pi r^2 \] where \( r \) is the radius of the circle. Since the question provides the diameter of the circle as 10 cm, you first need to determine the radius. The radius is half of the diameter: \[ r = \frac{\text{diameter}}{2} = \frac{10 \text{ cm}}{2} = 5 \text{ cm} \] Now, substitute the radius into the area formula: \[ \text{Area} = \pi (5 \text{ cm})^2 \] Calculating this gives: \[ \text{Area} = \pi \times 25 \text{ cm}^2 \] Using the approximation for π (π ≈ 3.14): \[ \text{Area} ≈ 3.14 \times 25 \text{ cm}^2 = 78.5 \text{ cm}^2 \] Thus, the area of the circle is approximately 78.5 cm², making this the correct answer. Understanding how to calculate the radius from the diameter and applying it in

To find the area of a circle, you can use the formula:

[ \text{Area} = \pi r^2 ]

where ( r ) is the radius of the circle. Since the question provides the diameter of the circle as 10 cm, you first need to determine the radius. The radius is half of the diameter:

[ r = \frac{\text{diameter}}{2} = \frac{10 \text{ cm}}{2} = 5 \text{ cm} ]

Now, substitute the radius into the area formula:

[ \text{Area} = \pi (5 \text{ cm})^2 ]

Calculating this gives:

[ \text{Area} = \pi \times 25 \text{ cm}^2 ]

Using the approximation for π (π ≈ 3.14):

[ \text{Area} ≈ 3.14 \times 25 \text{ cm}^2 = 78.5 \text{ cm}^2 ]

Thus, the area of the circle is approximately 78.5 cm², making this the correct answer. Understanding how to calculate the radius from the diameter and applying it in