document.write( "Question 1107158: Hello Online tutors!
\n" ); document.write( "Here's my question:\r
\n" ); document.write( "\n" ); document.write( "The surface area of a sphere is A=4pir^2(If you didn't get that it was 4 times pi times r to the second power. All one expression.
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\n" ); document.write( "If the area of a circle is the same as the surface area of a sphere, find the ratio of the radius of the sphere to the radius of the circle.
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Algebra.Com's Answer #722136 by Theo(13342)\"\" \"About 
You can put this solution on YOUR website!
the area of a circle is equal to pi * r^2.\r
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\n" ); document.write( "\n" ); document.write( "the surface area of a sphere is equal to 4 * pi * r^2.\r
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\n" ); document.write( "\n" ); document.write( "assume the radius of the circle is x.\r
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\n" ); document.write( "\n" ); document.write( "assume the radius of the sphere is y.\r
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\n" ); document.write( "\n" ); document.write( "the area of the circle becomes pi * x^2\r
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\n" ); document.write( "\n" ); document.write( "the surface area of the sphere becomes 4 * pi * y^2\r
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\n" ); document.write( "\n" ); document.write( "let A be the surface area of the sphere.\r
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\n" ); document.write( "\n" ); document.write( "since they're the same, let A also be the area of the circle.\r
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\n" ); document.write( "\n" ); document.write( "you get A = pi * x^2 and A = 4 * pi * x^2\r
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\n" ); document.write( "\n" ); document.write( "since the areas are the same, you get pi * x^2 = 4 * pi * y^2\r
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\n" ); document.write( "\n" ); document.write( "divide both sides of this equation by pi and you get x^2 = 4 * y^2\r
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\n" ); document.write( "\n" ); document.write( "divide both sides of this equation by y^2 and you get x^2 / y^2 = 4\r
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\n" ); document.write( "\n" ); document.write( "take the square root of both sides of this equation and you get x/y = 2\r
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\n" ); document.write( "\n" ); document.write( "solve for x to get x = 2y.\r
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\n" ); document.write( "\n" ); document.write( "solve for y to get y = 1/2 * x.\r
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\n" ); document.write( "\n" ); document.write( "x is the radius of the circle.\r
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\n" ); document.write( "\n" ); document.write( "y is the radius of the sphere.\r
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\n" ); document.write( "\n" ); document.write( "if the radius of the circle is 2 times the radius of the sphere, then the area of the circle will be the same as the surface area of the sphere.\r
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\n" ); document.write( "\n" ); document.write( "if the radius of the sphere is 1/2 times the radius of the circle, then the surface area of the sphere will be the same as the area of the circle.\r
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\n" ); document.write( "\n" ); document.write( "let's see if this is correct.\r
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\n" ); document.write( "\n" ); document.write( "assume the radius of the circle is 8 and the radius of the sphere is 4.\r
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\n" ); document.write( "\n" ); document.write( "the ratio of the radius of the circle to the radius of the sphere is 8/4 = 2.\r
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\n" ); document.write( "\n" ); document.write( "the ratio of the radius of the sphere to the radius of the circle is 4/8 = 1/2.\r
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\n" ); document.write( "\n" ); document.write( "the area of the circle is equal to pi * 8^2 which is equal to 64 * pi.\r
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\n" ); document.write( "\n" ); document.write( "the surface area of the sphere is equal to 4 * pi * 4^2 which is equal to 4 * pi * 16 which is equal to 64 * pi.\r
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\n" ); document.write( "\n" ); document.write( "the areas are the same which confirms that the solution is correct.\r
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\n" ); document.write( "\n" ); document.write( "the solution is that the ratio of the radius of the sphere to the radius of the circle is 1/2.\r
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