resonant length and wavelength of sound?

jnimagine

hi we did a lab with a resonant tube filled with water
we're supposed to figure out the relationship between the resonant length and the wavelength.
what we did was we filled up the resonant tube with water then put a tuning fork above it and found where that same sound was made.
Here is an example:
frequency of the tuning fork = 1024
1st resonant point:
resonant length: 7.8cm
0.23 ( lamda )
2nd resonant point: 24.5cm
0.72
and so on...

we figured out the resonant length in lamda by finding out velocity of sound in room temperature and finding out lamda by v/f
then resonant length (lamda) was figured out by res. length (cm) / wavelength (lamda)

now i have to figure out the relationship between the resonant length and the wavelength. first is the wavelength here referring to the wavelength figured out by v/f or lamda for resonant length?? is there a relation between the resonant length of the tube and the lamda resonant length?
can someone plz help me figure out any kind of relationship here??