I think you meant the two <em>segments</em><em> </em>are identical, if so then:

The times plus method.... is where a mixed number.... for example, to get the improper fraction of 3 1/4, you multiply 4 and three, and add that number with 1. (try writing it on a piece of paper, times between the whole number and denominator, and a plus between the whole number and the numerator.) anyway we are going to use the reverse for this.
SO the numerator is 17, and 17 is divisible by 5..... 3 times (u get where I'm going??) and there's 2 left over so...... the answer for that one should be 3 2/5
Since 3 x 5= 15+2 is 17 ;)))
Moving ON for the one....pick like 15 or 16 to be the denominator.... and subtract the 15 or 16 from 17, and the number you get is your numerator...
91.125 all you need to do is cube 4.5 or multiply 4.5 by itself 3 times so 4.5x4.5x4.5