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A roller used to flatten a cricket pitch has radius 0.7 m and length (height) 2 m. Find the area covered in one complete revolution (its curved surface area). Use π = .

Class 8MensurationMensuration
  • A17.6
  • B8.8
  • C9.8
  • D7.8

Step-by-Step Solution

Area in one revolution = CSA = 2πrh .
Answer: B) 8.8

Key idea: Surface area and volume of a cylinder

A cylinder is a circle stacked vertically. Two measurements: radius and height .

**Curved surface area (CSA) = 2π** (imagine 'unrolling' the curved surface — it becomes a rectangle of width 2π and height h).

**Total surface area (TSA) = 2πππ** (curved surface + two circular ends).

**Volume = π** (area of circular base × height).

Use π = 22/7 when is a multiple of 7; otherwise π ≈ 3.14.

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