Because you would start with turning 42 and 5/8 into 341/8 then do 341 divided by 8 to get 42.625 as the decimal, then start turning 393/5 into a decimal by 393 divided by 5 to get 78.6 as your decimal then add them together like this: 42.625 + 78.6 = 121.225 as your answer.
Claire threw the javelin 42.625 feet but grace threw the javelin 78.6 feet.
one way to describe the prime version of ABCD is that the sides are all 3 times that of the non- prime version. So they are when scaled by 3 .. the same.
