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Given that height(l) of a cone = 12 ft.

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Radius(r) of a cone = 10 ft.

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Surface area(T):

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\"\"                                   (Surface area of a cone)

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\"\"                  (Evalute powers)\"\"

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\"\"                                         (Add: \"\")

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\"\"                                 (Substitute \"\") \ \

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The surface area is approximately 690.8 square feets.