Which of the following is the correct VOLUME formula for a cylinder of radius r and height h?

Class 8MensurationMensuration

Step-by-Step Solution

Volume of a cylinder = area of circular base × height = π

r^{2}

h

. The option 2π

r h

is the curved surface area, and 2π

r (r + h)

is the total surface area.

Answer: A) π ×

r^{2} \times h

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

r

and height

h

.

**Curved surface area (CSA) = 2π

r h

** (imagine 'unrolling' the curved surface — it becomes a rectangle of width 2π

r

and height h).

**Total surface area (TSA) = 2π

r^{2} + 2

r h = 2

r (r + h)

** (curved surface + two circular ends).

**Volume = π

r^{2}

h

** (area of circular base × height).

Use π = 22/7 when

r

is a multiple of 7; otherwise π ≈ 3.14.

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