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The area of a circle is 38.5cm^(2) The c...

The area of a circle is `38.5cm^(2)` The circumference of the circle is

A

6.2cm

B

12.1cm

C

11cm

D

22cm

Text Solution

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The correct Answer is:
To find the circumference of the circle given its area, we can follow these steps: ### Step 1: Use the formula for the area of a circle. The area \( A \) of a circle is given by the formula: \[ A = \pi r^2 \] where \( r \) is the radius of the circle. ### Step 2: Set up the equation using the given area. We know the area of the circle is \( 38.5 \, \text{cm}^2 \). Therefore, we can write: \[ \pi r^2 = 38.5 \] ### Step 3: Solve for \( r^2 \). To isolate \( r^2 \), we can divide both sides by \( \pi \): \[ r^2 = \frac{38.5}{\pi} \] Using \( \pi \approx \frac{22}{7} \) for calculation, we have: \[ r^2 = \frac{38.5 \times 7}{22} \] ### Step 4: Calculate \( r^2 \). Now, calculate the right side: \[ r^2 = \frac{269.5}{22} \approx 12.25 \] ### Step 5: Find \( r \) by taking the square root. Now, take the square root of both sides to find \( r \): \[ r = \sqrt{12.25} = 3.5 \, \text{cm} \] ### Step 6: Use the radius to find the circumference. The circumference \( C \) of a circle is given by the formula: \[ C = 2\pi r \] Substituting the value of \( r \): \[ C = 2 \times \pi \times 3.5 \] Using \( \pi \approx \frac{22}{7} \): \[ C = 2 \times \frac{22}{7} \times 3.5 \] ### Step 7: Calculate the circumference. Now, calculate the circumference: \[ C = 2 \times \frac{22 \times 3.5}{7} = 2 \times 22 = 44 \, \text{cm} \] ### Final Answer: The circumference of the circle is \( 44 \, \text{cm} \). ---

To find the circumference of the circle given its area, we can follow these steps: ### Step 1: Use the formula for the area of a circle. The area \( A \) of a circle is given by the formula: \[ A = \pi r^2 \] where \( r \) is the radius of the circle. ...
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