a cubical box has edge 10 cm and another cuboidal box is 12.5 cm long, 10 cm and 8 cm high. Which box has the greater lateral surface area and by how much?
Answers
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Answer with step-by-step-explanation:
(i) Let the total surface areas of the cubical and cuboidal boxes be S₁ and S₂ respectively. Then,
S₁ = 6(edge)²
S₁ = 6 × 10² cm²
S₁ = 6 × 100 cm²
S₁ = 600 cm²
and, S₂ = 2(12.5×10 + 10×8 + 8×12.5) cm²
S₂ = 2( 125 + 80 + 100 ) cm²
S₂ = 610 cm²
Hence, S₂ - S₁ = 610 - 600 = 10 cm²
Thus, the cuboidal box has greater total surface area and is greater by 10 cm².
(ii) Let total surface areas of the cubical and cuboidal boxes be L₁ and L₂ respectively. Then,
L₁ = 4(edge)²
L₁ = 4 (10)² cm²
L₁ = 4 × 100 cm²
L₁ = 400 cm²
and, L₂ = 2(l + b) × h
L₂ = 2(12.5 + 10) × 8 cm²
L₂ = 2 × 22.5 × 8 cm²
L₂ = 360 cm²
Thus, the cuboidal boxes larger lateral surface area and is greater by 40 cm².