The semicircle of area 1250 π cm2 is inscribed inside a rectangle. The diameter of the semicircle coincides with the length of the rectangle. The area of the rectangle is:

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  1. 2000 cm2
  2. 4000 cm2
  3. 5000 cm2
  4. 3000 cm2

Answer (Detailed Solution Below)

Option 3 : 5000 cm2
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RRB NTPC Graduate Level Full Test - 01
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Detailed Solution

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Given:

Lenght of the Rectangle = Diameter of the semicircle

The semicircle of area =1250 π cm2 

Formula Used:

Area of semicircle = (π × r2)/2

Area of rectangle = Length × Width

Solution:

According to the given conditions;

Let the length of the rectangle = 2r

Width of the rectangle = r

Area of rectangle = 2r × r

Area of rectangle = 2r2

Area of semicircle = (π × r2)/2

1250 π = (π × r2)/2

⇒ r2 = 2500

⇒ r = 50

Area of rectangle = 2r × r = 2r2

Area of rectangle = 5000

Hence option 3 is correct.

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