document.write( "Question 1191585: A G.P has the second term as 9 and the fourth term is as 81.find the some of the first four term? \n" ); document.write( "

Algebra.Com's Answer #823435 by greenestamps(13200) $\"\"$ $\"About$

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\n" ); document.write( "The 4th term 81 is the 3nd term 9, multiplied by the common ratio twice:

\n" ); document.write( " $\"81=9r%5E2\"$
\n" ); document.write( " $\"9=r%5E2\"$
\n" ); document.write( " $\"r=3\"$ or $\"r=-3\"$

\n" ); document.write( "There are two possible answers to the problem.

\n" ); document.write( "(1) r=3; the first four terms are 3, 9, 27, 81; sum 120
\n" ); document.write( "(2) r=-3; the first four terms are -3,9,-27, 81; sum 60

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