Julia has to measure an object. she does not have a ruler. tell what julia could do to solve her problem.

Pretty much and in short, make up your own measure.

so... say you can use a tie or something with length, and use that to measure whatever object you need it for.

for example, I can just grab a string, cut it, and measure something, and the measurement may just be that the object is my string 6 times, so I know the length of the object is 6 times the length of the string I cut.

it doesn't quite matter how long the string cut was, all that matters is that is relable or referenciable for reuse.  Later on I could always just get the string measure and convert it to metric, once I found a ruler  or imperial units.

but in the short run, it doesn't really matter the length of the string cut, all that matters is that is referenciable, the object will be 6 times my string cut, here, in France, in Pluto, in Andromeda, anywhere.

bear in mind that the measure units we use today, are only usable because they're referenciable, so if I tell you 15 inches of something, you know how much 15 inches is, so that's all that matters.