Assuming you meant 0.9 meters....
You need to find the .9 of a meter first, so 90% of a meter. You do this by finding how many inches a meter (3 feet) is, which would be 36. 36/10= 3.6 inches, and 3.6*9= 32.4.
Now, to find the lengths of the pieces, divide 32.4 by 4:
32.4/4= 8.1 inches.
Hope this helps!