After a certain number of moves in a chess game, the ratio of black pieces to white pieces is 4 to 3. If there are 12 black pieces on the board, which proportion can be used to find the number of white pieces?
Black to white 4 : 3 12 : ? should be 9
What times 4 equals 12? 3! So if 3x4=12 then do 3x3 to find the white pieces;)