Welcome to the forum.
I am not sure I understand. Are you saying that the side lengths of two cubes are 35cm and 42cm, or are you asking what those lengths are?what are the side lengths of 2 different cubes that are 35cm and 42cm?
what are the side lengths of 2 different cubes that are 35cm and 42cm?
what is the ratio of the volume of the smaller ot the volume of the larger in simplest from?
I am assuming that 35 and 42 are the volumes of these cubes? A piece of info you left out.
Ratio
So their ratio would be 35:42 which can be reduced.
Side Lengths
Since they are cubes, all the sides are equal.
So find the cube root of 35, and the cube root of 42 and you should have their side lengths.
Cube root means that number that you multipy by itself 3 times to get the volume.
x • x • x = 35
x • x • x = 42