If half of the first part, a third of the second part and a quarter of the thrid part are equal, you can say that each of these 'divided' parts is equal to x.
Then, to get the first part, multiply x by 2, to get the second part, multiply x by 3 and to get the third part, multiply x by 4.
You get: 2x, 3x and 4x.
Their sum gives 243. Cna you solve it now?