say you have a level container that is 10cm by 10cm by 10cm. full of water, it would weight one kg. but say you can put no more than 400g into it. say you have only a metric ruler to determine this. how high can you fill the container?

my partial answer: i am not sure at all how to figure this out. i know that 1 cubic cm equals 1 gram. and that 1 cubic centimeter equals 1mL, but i don't know from there. thanks for helpin me.

400 g = .4 kg so it fills it .4 full

.4 * 10 = 4 cm

or
400 grams of water is 400 cubic centimeters (cc) of water
area of bottom times height = volume
10 * 10 * h = 400
h = 4