Algebra.Com's Answer #60269 by jim_thompson5910(35256)![\"\"](\"/images/stars/stars-13.gif\")  
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The formula for the surface area of a sphere is
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document.write( " , where A is surface area and r is the
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document.write( "radius of the sphere\r
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document.write( "a) use the formula to express r in terms of A and
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document.write( " rationalize the denominator. Explain your answer\r
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document.write( " Since we can solve for r by these steps\r
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document.write( " Start with the given equation\r
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document.write( " Divide both sides by  \r
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document.write( " Take the square root of both sides\r
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document.write( " Break up the square root using the identity  }\r
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document.write( " Break up the square root using the identity  }\r
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document.write( " Take the square root of 4 to get 2\r
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document.write( " Now rationalize the denominator by multiplying the numerator and denominator by  . This is equivalent to  which in other words eliminates the square root in the denominator\r
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document.write( " Multiply and reduce\r
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document.write( " Combine the square roots in the numerator\r
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document.write( "So now we have an equation in terms of A which is\r
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document.write( "b) suppose the surface area of a child's ball is
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document.write( " about 113 square inches. Find the radius of the
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document.write( " ball and explain your steps.\r
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document.write( "Since we have an equation in terms of A, we can plug in the given surface area (113 sq in) in for A and solve for r\r
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document.write( " Plug in A=113\r
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document.write( "Now lets approximate  to 3.14. From here on, all of our values will be approximations. So even though I don't show it (I'm unable to), keep this in mind.\r
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document.write( " Replace with 3.14\r
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document.write( " Multiply\r
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document.write( " Take the square root\r
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document.write( " Divide\r
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document.write( "So the for a ball with a surface area of 113 sq in., the radius is about 3 inches \n" );
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