What is the 6th term of the geometric sequence 4, 20, 100,...?

1 Answer
May 18, 2015

the geometric sequence given is:
#4 , 20 , 100# ...
When provided with a geometric sequence we must first calculate the common ratio #r#

#r# is obtained by dividing a term by its preceding term

1) #20/4 = 5#
2) #100/20 = 5#

for this sequence the common ratio # r = 5# the first term # a = 4#
and #n = 6#

The 6th term can be obtained through formula
# T_n = ar^(n-1) = 4 xx 5^((6-1))#
#= 4 xx 5^5#
#= 4 xx 3125 = 12500#