You want a riddle?

You have 2 pieces of string. Each piece of string takes exactly 1 hour to burn from end to end. The catch, however, is that the string burns at an uneven speed and each one is unique. Thus cutting the string in half is not guaranteed to produce 2 pieces of string that each burn for 30 minutes.

Knowing all of this, how can you use these 2 pieces of string (and some unlimited source of fire) to measure a 45 minute time period?

Please show a little etiquette and hide your answers with show text buttons