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The diameter of two circles are 32 cm an...

The diameter of two circles are 32 cm and 24 cm. Find the radius of the circle having its area equal to sum of the areas of the two given circle.

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To solve the problem step by step, we will find the radius of a new circle whose area is equal to the sum of the areas of two given circles with diameters of 32 cm and 24 cm. ### Step 1: Find the radii of the two circles. - For Circle C1 (diameter D1 = 32 cm): \[ r_1 = \frac{D_1}{2} = \frac{32 \, \text{cm}}{2} = 16 \, \text{cm} \] - For Circle C2 (diameter D2 = 24 cm): \[ r_2 = \frac{D_2}{2} = \frac{24 \, \text{cm}}{2} = 12 \, \text{cm} \] ### Step 2: Calculate the areas of the two circles. - Area of Circle C1: \[ \text{Area}_{C1} = \pi r_1^2 = \pi (16 \, \text{cm})^2 = 256\pi \, \text{cm}^2 \] - Area of Circle C2: \[ \text{Area}_{C2} = \pi r_2^2 = \pi (12 \, \text{cm})^2 = 144\pi \, \text{cm}^2 \] ### Step 3: Find the sum of the areas of the two circles. \[ \text{Total Area} = \text{Area}_{C1} + \text{Area}_{C2} = 256\pi + 144\pi = 400\pi \, \text{cm}^2 \] ### Step 4: Set the area of the new circle equal to the total area. Let the radius of the new circle (C3) be \( r_3 \). The area of Circle C3 is given by: \[ \text{Area}_{C3} = \pi r_3^2 \] Setting this equal to the total area: \[ \pi r_3^2 = 400\pi \] ### Step 5: Solve for \( r_3 \). Dividing both sides by \( \pi \): \[ r_3^2 = 400 \] Taking the square root of both sides: \[ r_3 = \sqrt{400} = 20 \, \text{cm} \] ### Final Answer: The radius of the new circle is \( 20 \, \text{cm} \). ---
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ICSE-AREA AND PERIMETER OF PLANE FIGURES-EXERCISE 20(C)
  1. The radii of two circle are 25 cm and 18 cm. Find the radius of the ci...

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  2. The radii of two circle are 48 cm and 13 cm. Find the area of the circ...

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  3. The diameter of two circles are 32 cm and 24 cm. Find the radius of th...

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  4. The radius of a circle is 5 m. Find the circumference of the circle wh...

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  5. The circle of largest area is cut from a rectangular piece of card-boa...

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  6. The following figure shows a square card-board ABCD of side 28 cm. Fou...

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  7. The radii of two cirlces are in the ratio 3 : 8. If the difference be...

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  8. The diameters of three circles are in the ratio 3 : 5 : 6. If the sum...

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  9. Find the area of a ring shaped region enclosed between two concentric ...

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  10. The circumference of a given circular park is 55 m. It is surrounded b...

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  11. There are two circular gardens A and B. The circumference of garden ...

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  12. A wheel had diameter 84 cm. Find how many complete revolutions must it...

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  13. The wheels of a car are of diameter 80 cm each. How many complete r...

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  14. An express train is running between two stations with a uniform speed....

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  15. The minute hand of a clock is 8 cm long. Find the area swept by the m...

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  16. The shaded portion of the figure, given alongside, shows two concentri...

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  17. In the figure, the area of the shaded portion is 770 cm^(2). If the ci...

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  18. The cost of fencing a circular field at the rate of Rs 240 per metre i...

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  19. Two circles touch each other externally. The sum of their areas is 58...

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  20. The given figure shows a rectangle ABCD inscribed in a circle as shown...

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