Puzzle time - measuring with fuses

[jon-nyc]

You have on hand two fuses (lengths of string), each of which will burn for exactly 1 minute.  They do not, however, burn uniformly along their lengths.  Can you nevertheless use them to measure 45 seconds?

[Horace]

Doesn't seem likely. Is the problem missing some specification? Do they need to be identical?

[jon-nyc]

No need to be identical. Not missing anything.

(Except the presumption that you possess a lighter or match)

[Horace]

Oh, yeah. Start one fuse from both ends and one from one end, using your magic Lighter of Exactitude. When the fuse lit on both ends is gone (30 seconds), start the unlit end of the other one, which will have 30 seconds left and which will burn in 15.

[jon-nyc]

And Bob’s your uncle.