Reply To: The Riddle Thread….

15, 8, 12, 80 ==> 15 x 2 x 8^2 / (12 x 2) = 80

18, 7, 6, 147 ==> 18 x 2 x 7^2 / (6 x 2) = 147

19, 6, 12, ? ==> 19 x 2 x 6^2 / (12 x 2) = 57