document.write( "Question 146646: A circle has a chord of length 8 that is tangent to a smaller, concentric circle.Find the area between the two circles:\r
\n" ); document.write( "\n" ); document.write( "a) 16 (note each of the answers listed have a pie sign next to them.)
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Algebra.Com's Answer #107081 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
It always helps to draw a picture\r
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\n" ); document.write( "\n" ); document.write( "note: \"R\" is the radius of the larger circle and \"r\" is radius of the smaller circle. Also, I divided the chord in half. \r
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\n" ); document.write( "\n" ); document.write( "From the picture, we can see that the radius R is the hypotenuse of the triangle with legs of \"r\" and 4. So this means\r
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\n" ); document.write( "\n" ); document.write( "\"4%5E2%2Br%5E2=R%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "\"16%2Br%5E2=R%5E2\" Square 4 to get 16\r
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\n" ); document.write( "\n" ); document.write( "\"16=R%5E2-r%5E2\" Subtract \"r%5E2\" from both sides\r
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\n" ); document.write( "\n" ); document.write( "So \"R%5E2-r%5E2=16\"\r
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\n" ); document.write( "\n" ); document.write( "Now the area of the larger circle is \"A=pi%2AR%5E2\" and the area of the smaller circle is \"A=pi%2Ar%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "Since we want the area between the two circles, we must subtract the two areas to get: \"pi%2AR%5E2-pi%2Ar%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "\"pi%28R%5E2-r%5E2%29\" Factor out the GCF \"pi\"\r
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\n" ); document.write( "\n" ); document.write( "\"pi%2816%29\" Plug in \"R%5E2-r%5E2=16\". In other words, replace \"R%5E2-r%5E2\" with 16\r
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\n" ); document.write( "\n" ); document.write( "\"16pi\" Rearrange the terms\r
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\n" ); document.write( "\n" ); document.write( "So the area between the two circles is \"16pi\"
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