Box P is a cuboid and box Q is a cube, with the sizes shown. Both are closed boxes made of thin plywood. Which needs more plywood, and by how much?

Class 8MensurationMensuration

Step-by-Step Solution

2 (60 \times 40 + 40 \times 50 + 60 \times 50) = 2 (2400 + 2000 + 3000) = 14800 cm^{2}

. Q:

6 \times 5 0^{2} = 15000 cm^{2}

. Q needs

200 cm^{2}

more.

Answer: A)

Q, b y 200 cm^{2}

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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