document.write( "Question 961014: Find the common ratio of the infinite geometric series with the given sum and first term s=7/9 a1=7/10 \n" ); document.write( "

Algebra.Com's Answer #587374 by rothauserc(4718) $\"\"$ $\"About$

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We use the following formula for infinite geometric series sum
\n" ); document.write( "S = a(1 / (1-r)) where S is the sum, a is first term and r is the common ratio, therefore
\n" ); document.write( "7/9 = (7/10)(1 / (1-r))
\n" ); document.write( "7/9 = 7 / (10(1-r))
\n" ); document.write( "cross multiply fractions
\n" ); document.write( "70(1-r) = 63
\n" ); document.write( "1-r = 63/70 = 9/10
\n" ); document.write( "r = 1 - (9/10) = 1/10
\n" ); document.write( "the common ratio(r) is 1/10
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