$\"\"$

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Observe the figure :

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The centroids are $\"\"$ , $\"\"$ and $\"\"$ .

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The center of mass $\"\"$ is $\"\"$ and $\"\"$ .

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Where $\"\"$ . $\"\"$ is the total mass of the system.

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Now calculate $\"\"$ :

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$\"\"$

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Now calculate $\"\"$ :

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$\"\"$

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Now calculate $\"\"$ :

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$\"\"$ .

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$\"\"$

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Find the value of $\"\"$ :

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$ .

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Find the value of $\"\"$ :

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$ .

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The center of the mass is $\"\"$ .

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$\"\"$

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The center of mass is $\"\"$ .