How to do this question plz answer me step by step plzz

Answer:
4 cm
Step-by-step explanation:
At 12 cm depth, the depth is 12/15 = 4/5 of the height of the container.
When the container is tipped on its side, so its height is 5 cm, the depth will still be 4/5 of the height.
(4/5)(5 cm) = 4 cm
The depth will be 4 cm.