Question

Twelve is the geometric mean of 9 and what number?

Answer 1

geometric mean of two numbers a and b is given by= \(\sqrt{ab}\)
here geometric mean is 12, a is 9 , we've to find b
\[12=\sqrt{9b}\]
square both sides
\[144=9b\]
divide both sides by 9
we get
\[16=b\]
the other no. is 16