Answer:
30 is the geometric mean between 9 and 51.
Step-by-step explanation:
i multiplied 30 by 2 because there are two numbers in the set of numbers that have a mean of 30.
30*2=60
i then subtracted 9, working back from finding the mean,
60-9=51.
check your work!
51+9=60/2=30
your answer is 51