Question #48769

1 Answer
Aug 2, 2017

#24.5#

Explanation:

#ar^(n-1)=a_n#

#ar^2=8#
#ar^4=14#

#(ar^4)/(ar^2)=14/8#
#r^2=7/4#
#r=sqrt(7/4)#

Method 1:
#a_7=ar^6=ar^4*r^2=14*7/4=24.5#

Method 2:
#ar^2=8#
#a(7/4)=8#
#a=8*(4/7)=4.57142857#
#ar^6=4.57142857*(sqrt(7/4))^6=24.5#