Ahmad's mum buys a cereal box shaped like a cuboid. The box is 20 cm long, 8 cm wide and 28 cm tall. If the cereal box were unfolded completely into a flat net, what would be the total area of the net?
Show Worked Solution
Worked Solution
Step 1: Identify the three pairs of faces on the cuboid.
• Top and bottom faces: length × width = 20 × 8 = 160 cm²
• Front and back faces: length × height = 20 × 28 = 560 cm²
• Left and right faces: width × height = 8 × 28 = 224 cm²
Step 2: Each pair contains 2 identical faces, so multiply each area by 2.
• 2 × 160 = 320 cm²
• 2 × 560 = 1120 cm²
• 2 × 224 = 448 cm²
Step 3: Add all six face areas.
Total = 320 + 1120 + 448 = 1888 cm²
Alternative formula: Total Surface Area = 2(lb + lh + bh)
= 2(160 + 560 + 224) = 2 × 944 = 1888 cm²
Correct answer: 1888 cm²
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