Advanced-WS-G8- Practice Problems on Surface Area of Cubes and ... - Free Printable

Let’s solve each problem one by one, step by step.

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Problem 1:

We have:
- A cube with edge = 7 cm
- A cuboid measuring 7 cm × 4 cm × 8 cm (note: “am” is likely a typo for “cm”)

Volume of cube = edge³ = 7 × 7 × 7 = 343 cm³

Volume of cuboid = length × breadth × height = 7 × 4 × 8
First, 7 × 4 = 28
Then, 28 × 8 = 224 cm³

Compare: 343 > 224 → Cube has more volume.

✔ Final Answer for Problem 1: Cube

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Problem 2:

Cuboid: 9 cm long, 5 cm broad, 4 cm high
→ Volume = 9 × 5 × 4
9 × 5 = 45
45 × 4 = 180 cm³

Cube: edge = 5 cm
→ Volume = 5 × 5 × 5 = 125 cm³

Compare: 180 > 125 → Cuboid has greater volume.

✔ Final Answer for Problem 2: Cuboid

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Problem 3:

Brick of ice-cream: length = 25 cm, breadth = 10 cm, height = 8 cm
It’s a cuboid → Volume = l × b × h = 25 × 10 × 8

25 × 10 = 250
250 × 8 = 2000 cm³

✔ Final Answer for Problem 3: 2000 cm³

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Problem 4:

One brick: 15 cm × 8 cm × 5 cm
Wall: 15 m × 10 m × 8 m

⚠️ Units are different! Brick is in cm, wall is in meters. Convert everything to same unit.

Convert wall dimensions to cm:
1 m = 100 cm
So,
Length = 15 m = 15 × 100 = 1500 cm
Breadth = 10 m = 10 × 100 = 1000 cm
Height = 8 m = 8 × 100 = 800 cm

Volume of wall = 1500 × 1000 × 800
That’s huge — let’s compute step by step:

First, 1500 × 1000 = 1,500,000
Then, 1,500,000 × 800 = ?

Break it down:
1,500,000 × 800 = 1,500,000 × 8 × 100
= (1,500,000 × 8) × 100
1,500,000 × 8 = 12,000,000
Then × 100 = 1,200,000,000 cm³

Now, volume of one brick = 15 × 8 × 5
15 × 8 = 120
120 × 5 = 600 cm³

Number of bricks needed = Total wall volume ÷ One brick volume
= 1,200,000,000 ÷ 600

Divide:
1,200,000,000 ÷ 600 = (1,200,000,000 ÷ 100) ÷ 6 = 12,000,000 ÷ 6 = 2,000,000

✔ Final Answer for Problem 4: 2,000,000 bricks

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Final Answer:
1. Cube
2. Cuboid
3. 2000 cm³
4. 2000000