Multiple choice

A hollow right circular cylinder with height $8$ cm and base radius $7$ cm is opened out into a rectangle. What are the length and breadth of the rectangle respectively ?

  1. $22$ cm, $16$ cm
  2. $44$ cm , $8$ cm
  3. $22$ cm, $8$ cm
  4. $44$ cm, $16$ cm
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When a cylinder is opened into a rectangle, the height of the cylinder becomes one side of the rectangle (8 cm) and the circumference of the base becomes the other side. The circumference is 2 * pi * r = 2 * 3.14 * 7 = 44 cm (using pi approx 22/7).

AI explanation

When a hollow cylinder is opened into a rectangle, its length equals the circumference of the base and its breadth equals the height. The circumference is 2 times pi times r, which is 2 times 22 over 7 times 7, giving a length of 44 cm. The breadth is the given height of 8 cm, so the dimensions are 44 cm and 8 cm.

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