A cylindrical tin has radius 7 cm and height 20 cm. Find the area of the label paper that wraps around its curved surface only. Use π = $\frac{22}{7}$ .

Class 8MensurationMensuration

Step-by-Step Solution

Label covers the curved surface: CSA = 2πrh

= 2 \times \frac{22}{7} \times 7 \times 20 = 2 \times 22 \times 20 = 880 cm^{2}

Answer: C) 880

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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