What is the common ratio of the geometric sequence 7, 28, 112,...?

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Answer 1 · 2014-09-19T21:46:02

The common ratio for this problem is 4.

The common ratio is a factor that when multiplied by the current term results in the next term.

First term: #7#

#7 * 4 =28#

Second term: #28#

#28 * 4=112#

Third term: #112#

#112 * 4=448#

Fourth term: #448#

This geometric sequence can be further described by the equation:

#a_n =7*4^(n-1)#

So if you want to find the 4th term , #n=4#

#a_4=7*4^(4-1)=7*4^(3)=7*64=448#

Note:

#a_n =a_1r^(n-1)#

where #a_1# is the first term, #a_n# is the actual value returned for a specific #n^(th)# term and #r# is the common ratio.