Answer: [D]: 4 inches .
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Explanation:
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Formula for Volume of a cone:
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V = \(\pi\) r² h (1/3) ;
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Given: V = 251.2 in³ ;
h = 15 in.
π = 3.14 ;
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Plug in our given values to find, "r" :
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251.2 in³ = (3.14) r² (15 in.) (1/3) ;
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251.2 in³ = (15.7 in.) r²
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Divide each side of the equation by: "(15.7 in.)" ;
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251.2 in³ / (15.7 in.) = (15.7 in.) * r² / (15.7 in.) ;
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r² = 16
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Now, take the positive "square root" of EACH SIDE of the equation;
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to isolate "r" on one side of the equation ; and to solve for "r" ;
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√(r²) = √(16 in²) ;
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r = 4 inches; which is Answer choice: [D] .
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