First, we need to work out the length of each 'part' of string. We are told Jake cuts the string into the ratio 4:3:2 , so there are (4+3+2=9) 9 parts in total. To work out how long each part is, we calculate 126/9=14. So, each part is 14cm long.
Then we need to work out the lengths of the pieces of string he has cut. We do this by multiplying the number of parts by 14cm, so 4x14=56 , 3x14=42 , 2x14=28. Therefore the answer to the question is 56cm, 42cm, and 28cm.