The answer is: " 119.04 cm² " .
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Explanation:
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There are 4 equal triangles.
The formula for the surface area, "SA", of a triangle, is:
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SA = (1/2) (base length) * (height);
that is: SA = (1/2) * (b) * h).
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So, we plug in the given values in the figure;
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SA = (1/2) * (6.4 cm) * (6.1 cm) = 19.52 cm² ;
Then multiply this value by "4" (there are 4 "equal area triangles" on the surface of this figure):
19.52 cm² * 4 = 78.08 cm² .
The remaining surface area is the "square base" of this figure, which is a square with equal length and height;
so the area = 6.4 cm * 6.4 cm = 40.96 cm².
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So add the following:
78.08 cm² + 40.96 cm² = 119.04 cm² .
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The answer is: 119.04 cm² .
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