document.write( "Question 374088: The sum of the area s of two circles is 65pi square feet. The length of a radius of the larger circle is one foot less than twice the length of the radius of the smaller circle. Find the length of a radius of each circle. \n" ); document.write( "
Algebra.Com's Answer #266327 by rfadrogane(214)\"\" \"About 
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The sum of the area s of two circles is 65pi square feet. The length of a radius of the larger circle is one foot less than twice the length of the radius of the smaller circle. Find the length of a radius of each circle.\r
\n" ); document.write( "\n" ); document.write( "Sol'n:
\n" ); document.write( " let R - radius of big circle
\n" ); document.write( " r - radius of small circle
\n" ); document.write( " A1+A2 = 65pi
\n" ); document.write( " R^2pi + r^2pi = 65pi, eliminating pi on both side
\n" ); document.write( " R^2 + r^2 = 65 ----(1)
\n" ); document.write( " R = 2r-1 -----(2)
\n" ); document.write( " substitute (2)into (1),
\n" ); document.write( " (2r-1)^2 + r^2 = 65
\n" ); document.write( " 4r^2 - 4r + 1 r^2 = 65
\n" ); document.write( " 5r^2 - 4r - 64 = 0, factor then equate to zero to find the value of r.
\n" ); document.write( " r = 4---acceptable
\n" ); document.write( " r = -3.2----absurd,
\n" ); document.write( " thus,
\n" ); document.write( " r = 4 ft. -----ans.
\n" ); document.write( " R = 2(4)-1 = 7 ft. -----ans.
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