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Given a random spandrel, find the expressions for the differential elements of area and the coordinates of its centroid needed to determine the location of the centroid by integration. 

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The area of the strip, dA is the width times the height of the strip.

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The narrow width of the element is either $dx$ or $dy$ 

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The coordinates of the centroid are found by averaging the coordinates of the top and bottom of the strip.

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Determine the properties of the differential strip in terms of the known coordinates.

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$dA$ = [[0]]

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$\\bar{x}_{el}$ = [[1]] 

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$\\bar{y}_{el}$ =[[2]]  

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