Answer :
There are 1,000 mm in a meter. Therefore, if he wants to cut a piece of wood that is 1.2 m long into three equal parts, each part would be 400 mm long
1.2 meter cut to 3 is 0.4 meters
0.4 meters is the same as 40cm
so 400mm in one length
0.4 meters is the same as 40cm
so 400mm in one length