Answer :

2 halves (1/2) make a whole (1/1) and there are 4 wholes and 1 half
so 2 times 4=8 
8+1=9
so nine halves
RhysH
4 1/2 = 4.5
half a meter = 0.5 = 1/2
then divide 4.5 by 0.5
4.5/0.5
when dividing by 0.5 or 1/2 it is the same as multiplying by 2 so..
4.5 x 2 = 9
so 9 half meters measure 4 1/2