document.write( "Question 706416: Three circles are tangent externally to each other. The lines of centers are 12, 18 and 16 cm respectively. Find the length of the radius of each circle. \n" ); document.write( "
Algebra.Com's Answer #435254 by ankor@dixie-net.com(22740)\"\" \"About 
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Three circles are tangent externally to each other.
\n" ); document.write( " The lines of centers are 12, 18 and 16 cm respectively.
\n" ); document.write( " Find the length of the radius of each circle.
\n" ); document.write( ":
\n" ); document.write( "Draw out the the three different size circles touching each other,
\n" ); document.write( "Label the distances between the centers and the radii r1, r2, r3,
\n" ); document.write( "derive 3 equations from this
\n" ); document.write( ":
\n" ); document.write( "r1 + r2 = 12
\n" ); document.write( "r1 + r3 = 16
\n" ); document.write( "r2 + r3 = 18
\n" ); document.write( ":
\n" ); document.write( "Arrange these equations for elimination, mult the 3rd equation by -1:
\n" ); document.write( "r1 + r2 + 0 = 12
\n" ); document.write( "r1 + 0 + r3 = 16
\n" ); document.write( "0 - r2 - r3 = -18
\n" ); document.write( "--------------------addition, eliminates r2 and r3, find r1
\n" ); document.write( "2(r1) = 10
\n" ); document.write( "r1 = 10/2
\n" ); document.write( "r1 = 5 is the radius of the smaller circle
\n" ); document.write( "then
\n" ); document.write( "5 + r2 = 12
\n" ); document.write( "r2 = 12 - 5
\n" ); document.write( "r2 = 7 is the radius of the middle circle
\n" ); document.write( "and
\n" ); document.write( "7 + r2 = 18
\n" ); document.write( "r2 = 11 is the radius of the larger circle
\n" ); document.write( ":
\n" ); document.write( "You can check this for yourself \n" ); document.write( "
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