divide curve to a given % lenght in GH

Hi there

I am new in GH and learning how to run some basic task to hopefully move  to more advance issues soon

I am now stuck to this point : 

" I need to find the way to split a set of curves to a specific % lenght  ( ex 25% = first quarter , 50% = mid point and so on ) "

Does anyone know how to solve this problem ?

many thanks in advance

cheers

Ivan