document.write( "Question 70874: In 1943, during world war II, copper was needed for the war effort, so pennies were made of lead. A lead penny had a diameter of 1.8 cm and a thickness of 0.1 cm. If lead has a mass of 11.4 grams per cm^3, what was the mass of a lead penny?
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Algebra.Com's Answer #50661 by ankor@dixie-net.com(22740)\"\" \"About 
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In 1943, during world war II, copper was needed for the war effort, so pennies were made of lead. A lead penny had a diameter of 1.8 cm and a thickness of 0.1 cm. If lead has a mass of 11.4 grams per cm^3, what was the mass of a lead penny?
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\n" ); document.write( "A penny is in the shape of a cylinder so we can use the that formula:
\n" ); document.write( "V = pi*r^2*h, in our problem: r = 1.8/2 = .9 cm; h = .1 cm
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\n" ); document.write( "V = pi * .9^2 * .1
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\n" ); document.write( "V = pi * .81 * .1
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\n" ); document.write( "V = .254469 cu cm
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\n" ); document.write( "Mass = vol * density:
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\n" ); document.write( "Mass = .254469 * 11.4
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\n" ); document.write( "Mass = 2.9 grams \n" ); document.write( "
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