challenge 5 this is another rectangular tiling but this time we are given fewer clues use the 25 by 25 square to figure out the dimensions of all the other squares and the value of x in particular

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.