The answer is: " 52 mm² " .
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Explanation: There are a total of 5 (FIVE) sides, or "faces"; covering the surface;
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2 (TWO) triangles of equal area; and
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3 (THREE) rectangles of equal area ;
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The area of the rectangle given:
A = L * w = (4mm)*(3mm) = 12 mm² ;
Multiply this by "3" ; since there are 3 (THREE) such rectangles of equal area on the surface:
→ (12 mm²) * 3 = 36 mm² ;
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Now, calculate the area of 1 (ONE) of the 2 (TWO) triangles; both are equal in area/dimensions:
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A = (1/2) * b * h = (1/2) * (4mm) * (4mm) = 8 mm² ;
Multiply this by "2" ; since there are 2 (TWO) such triangles of equal area on the surface;
→ (8 mm²) * (2) = 16 mm² ;
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Now, to find the TOTAL surface area:
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We add: 36 mm² + 16 mm² = 52 mm² ; → which is our answer.
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