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The perimeter of a circle is equal to th...

The perimeter of a circle is equal to the perimeter of a square. Then.their area are in the ratio (use `pi = 22/7`)

A

`4:1`

B

`3:7`

C

`14:11`

D

`22:7`

Text Solution

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The correct Answer is:
To solve the problem where the perimeter of a circle is equal to the perimeter of a square, and we need to find the ratio of their areas, we can follow these steps: ### Step 1: Understand the Perimeters The perimeter (circumference) of a circle is given by the formula: \[ C = 2\pi r \] where \( r \) is the radius of the circle. The perimeter of a square is given by: \[ P = 4a \] where \( a \) is the length of one side of the square. ### Step 2: Set the Perimeters Equal According to the problem, the perimeter of the circle is equal to the perimeter of the square: \[ 2\pi r = 4a \] ### Step 3: Simplify the Equation We can simplify this equation to find a relationship between \( r \) and \( a \): \[ \pi r = 2a \] \[ r = \frac{2a}{\pi} \] ### Step 4: Calculate the Areas Now we need to find the areas of both shapes. The area of the circle is given by: \[ A_{circle} = \pi r^2 \] Substituting \( r \) from the previous step: \[ A_{circle} = \pi \left(\frac{2a}{\pi}\right)^2 \] \[ A_{circle} = \pi \cdot \frac{4a^2}{\pi^2} \] \[ A_{circle} = \frac{4a^2}{\pi} \] The area of the square is given by: \[ A_{square} = a^2 \] ### Step 5: Find the Ratio of Areas Now we can find the ratio of the area of the circle to the area of the square: \[ \text{Ratio} = \frac{A_{circle}}{A_{square}} = \frac{\frac{4a^2}{\pi}}{a^2} \] \[ \text{Ratio} = \frac{4}{\pi} \] ### Step 6: Substitute the Value of \(\pi\) Using the value of \(\pi = \frac{22}{7}\): \[ \text{Ratio} = \frac{4}{\frac{22}{7}} = 4 \cdot \frac{7}{22} = \frac{28}{22} = \frac{14}{11} \] ### Final Answer The ratio of the areas of the circle to the square is: \[ \frac{14}{11} \] ---
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