help me with this SAT 2 question
If three numbers log(sub a), log(sub b), and log(sub c) in that order form a arithmetic progression, which of the following is true?

a) b=ac
b) c=ab
c)b=(a+c)/2
d)b^2=ac
e)b^2=a+c

Question

help me with this SAT 2 question 
If three numbers log(sub a), log(sub b), and log(sub c) in that order form a arithmetic progression, which of the following is true?

a) b=ac
b) c=ab
c)b=(a+c)/2 
d)b^2=ac 
e)b^2=a+c

anonymous · Answer

from the property of arithmetic progression:
2*log(sub a)=log(sub a)+log(sub c)
log[(sub b)^2]=log(sub a*sub c)
compare it and find the relation between a,b,c
it will be b^2=ac

alexwee123 · Answer

makes total sense now
 thanks :D

anonymous · Answer

welcome