Three identical cubes, each of edge 5 cm, are glued face to face in a row to form a cuboid. What is the total surface area of the cuboid?

350 cm²Correct answerYour answer375 cm²Correct answerYour answer400 cm²Correct answerYour answer450 cm²Correct answerYour answer

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CorrectNot quiteAnswer A

Correct answer: A

The cuboid measures 15 cm × 5 cm × 5 cm.
Total surface area = $2 \times (15 \times 5 + 5 \times 5 + 15 \times 5) = 2 \times 175 = 350$ cm².

Worth noting

450 cm² adds the three cubes' surfaces $(3 \times 150)$ but the four glued faces are hidden. 400 cm² hides only two faces.

Ten questions from Mensuration: Areas and Volumes, at your own pace.

Ten questions from Mensuration: Areas and Volumes, at your own pace.

Explanation