The third proportional of two numbers 9 and 24 is ________.

Let the third proportional of 9 and 24 be x.
By the definition of continued proportion, if a, b, and c are in continued proportion, then:

b
a
​
=
c
b
​
⟹c=
a
b
2

​

Here, a=9 and b=24:

x=
9
24
2

​

x=
9
576
​
=64
Therefore, the third proportional is 64.