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A wire, when bent in the form of a squar...

A wire, when bent in the form of a square, encloses an area of 196 `cm^(2)`. If the same wire is bent to form a circle, find the area of the circle.

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To solve the problem step-by-step, we will follow these steps: ### Step 1: Find the side of the square Given the area of the square is 196 cm², we can use the formula for the area of a square: \[ \text{Area} = \text{side}^2 \] Let the side of the square be \( x \): \[ x^2 = 196 \] To find \( x \), we take the square root of both sides: \[ x = \sqrt{196} \] ### Step 2: Calculate the square root of 196 Finding the square root of 196: \[ \sqrt{196} = 14 \quad (\text{since } 14 \times 14 = 196) \] ### Step 3: Find the perimeter of the square The perimeter \( P \) of a square is given by: \[ P = 4 \times \text{side} \] Substituting the side we found: \[ P = 4 \times 14 = 56 \text{ cm} \] ### Step 4: Use the perimeter to find the circumference of the circle Since the wire is bent to form a circle, the circumference \( C \) of the circle is equal to the perimeter of the square: \[ C = 56 \text{ cm} \] ### Step 5: Find the radius of the circle The formula for the circumference of a circle is: \[ C = 2\pi r \] Setting the circumference equal to 56 cm: \[ 56 = 2\pi r \] To find the radius \( r \), we rearrange the equation: \[ r = \frac{56}{2\pi} = \frac{28}{\pi} \] Using \( \pi \approx \frac{22}{7} \): \[ r = \frac{28 \times 7}{22} = \frac{196}{22} = \frac{98}{11} \text{ cm} \] ### Step 6: Find the area of the circle The area \( A \) of a circle is given by: \[ A = \pi r^2 \] Substituting the radius we found: \[ A = \pi \left(\frac{98}{11}\right)^2 \] Calculating \( r^2 \): \[ \left(\frac{98}{11}\right)^2 = \frac{9604}{121} \] Thus, the area becomes: \[ A = \pi \times \frac{9604}{121} \] Using \( \pi \approx \frac{22}{7} \): \[ A = \frac{22}{7} \times \frac{9604}{121} \] Calculating: \[ A = \frac{22 \times 9604}{7 \times 121} = \frac{211328}{847} \] Now, performing the division: \[ A \approx 249.4 \text{ cm}^2 \] ### Final Answer The area of the circle is approximately \( 249.4 \text{ cm}^2 \). ---
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ICSE-AREA OF A TRAPEZIUM AND A POLYGON-EXERCISE 20(D)
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  7. Find the area of the shaded portion in each of the following diagrams...

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  8. Find the area of the shaded portion in each of the following diagrams...

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  9. The radii of the inner and outer circumferences of a circular-running...

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  10. A circular field of radius 105 m has a circular path of uniform width...

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  11. There is a path of uniform width 7 m round and outside a circular gar...

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  12. A wire, when bent in the form of a square, encloses an area of 484 c...

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  13. A wire, when bent in the form of a square, encloses an area of 196 cm...

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  16. A bicycle wheel, diameter 56 cm, is making 45 revolutions in every 10...

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  17. A roller has a diameter of 1.4 m. Find : (i) its circumference ...

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  18. Find the area of the circle, length of whose circumference is equal t...

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  19. A piece of wire of length 108 cm is bent to form a semicircular arc b...

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