Answer:
The formula for volume is l x w x h.
Explanation
To find the missing link, we do the equation backwards.
l x 2.5 x 5 = 75
If we divide 75 by 5 then by 2.5, we get 6 which becomes our length.
To check, do 5 x 2.5 x 6 which should equal 75
6 is your length