Find four geometric means between 12 and 93,312.

Question

anonymous · Answer

A) 72, 432, 2,592, 15,552
		
B) 18,672, 37,332, 55,992, 74,652
		
C) 72, 78, 84, 90
		
D) 15,634, 31,256, 46,878, 62,500

jdoe0001 · Answer

$\bf \cfrac{12}{{\color{brown}{ x}}}=\cfrac{{\color{brown}{ x}}}{93,312}\qquad {\color{brown}{ geometric\ mean}}$

anonymous · Answer

So do I cross multiply? 12 by 93,312?

jdoe0001 · Answer

yeap and solve for "x"

anonymous · Answer

Do you think you could show me? I am a little confused on how I should set it up.

solomonzelman · Answer

Got disconnected, sorry.

$\normalsize\color{blue}{  12 \times r^5=93,312  }$

find the Common Ratio, and then find the means. Good luck!

jdoe0001 · Answer

ohhh.... "FOUR" geometric means.... hmmm check SolomonZelman 's line

I didn't read the 4 part there =)

anonymous · Answer

@SolomonZelman Is it A?

solomonzelman · Answer

Are you trying to guess the answer? Show what have you done to find the common ratio for me please.

anonymous · Answer

I checked for every answer and option A had a common ratio of 6 right? So I plugged it in the equation you gave me which equaled = 93,312. @SolomonZelman

solomonzelman · Answer

Holy moses, you aren't supposed to go backwards like this, because what if you didn't have the options, huh ?
I forgive you this time, but please... for your own sake do the process in order.

Yes, it is A.

anonymous · Answer

But the question was multiple choice so it worked for this question... Thank you though.

solomonzelman · Answer

Yes, but not all questions are multiply choice. In fact, when I studied in Russia (up to 6th grade) I never had multiply choice, everything was hard.