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A copper wire when bent in the form of a...

A copper wire when bent in the form of a square encloses an area of `121 cm^(2)`. Y the same wire is bent in the form of a circle, find the area enclosed by it.

A

`184cm^(2)`

B

`164cm^(2)`

C

`154cm^(2)`

D

`174cm^(2)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem step by step, we will follow these steps: ### Step 1: Understand the area of the square The area of the square is given as \(121 \, \text{cm}^2\). The formula for the area of a square is: \[ \text{Area} = a^2 \] where \(a\) is the length of one side of the square. ### Step 2: Find the side length of the square To find the side length \(a\), we take the square root of the area: \[ a = \sqrt{121} = 11 \, \text{cm} \] ### Step 3: Calculate the perimeter of the square The perimeter \(P\) of a square can be calculated using the formula: \[ P = 4a \] Substituting the value of \(a\): \[ P = 4 \times 11 = 44 \, \text{cm} \] ### Step 4: Relate the perimeter of the square to the circumference of the circle When the wire is bent into the shape of a circle, the perimeter of the square is equal to the circumference \(C\) of the circle: \[ C = P = 44 \, \text{cm} \] ### Step 5: Use the circumference to find the radius of the circle The formula for the circumference of a circle is: \[ C = 2\pi r \] Setting this equal to the perimeter we found: \[ 44 = 2\pi r \] Now, we can solve for \(r\): \[ r = \frac{44}{2\pi} = \frac{22}{\pi} \] Using \(\pi \approx \frac{22}{7}\): \[ r = \frac{22 \times 7}{22} = 7 \, \text{cm} \] ### Step 6: Calculate the area of the circle The area \(A\) of a circle is given by the formula: \[ A = \pi r^2 \] Substituting the value of \(r\): \[ A = \pi (7^2) = \pi \times 49 \] Using \(\pi \approx \frac{22}{7}\): \[ A = \frac{22}{7} \times 49 = 22 \times 7 = 154 \, \text{cm}^2 \] ### Final Answer The area enclosed by the wire when bent in the form of a circle is: \[ \boxed{154 \, \text{cm}^2} \] ---
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Knowledge Check

  • A copper wire when bent in the form of a square, encloses an area of 121 m^2 . If the same wire is bent to form a circle, the area enclosed by it would be :

    A
    `122 m^2`
    B
    `112 m^2`
    C
    `154 m^2`
    D
    `308 m^2`
  • A wire, bent in the form of a square, encloses an area of 121 cm^2 . If the same wire is bent in the form of a circle, then the circumference of the circle is:

    A
    11 cm
    B
    22 cm
    C
    33 cm
    D
    44cm
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