Sounds a bit tight to me . they need to start outside the window line and with the ruffles would expect to need total of 150, but why not try it with an old sheet or towels
112 CM is a standard size for curtain width - if your window is 100 inches, 112 CM will be too small. Make sure the curtains are being sold in inches, so you are comparing simlar measurements.
I forsee problems when you're dealing with inches and centimetres...you really need to stick with one - the one that the curtains are sold in ie centimetres.
And now for a sensible answer....
If you want the curtains to be 'full' when they're drawn, you'll need at least 1.75 times the width of the window and preferably 2 times.
Thank you all.
We have ordered now..if I try to explain it's going to sound garbled..but, they will possibly be to wide, if that's possible with the amount on order.