Adrawing of a surfboard in a catalog shows its length as 8 4/9 inches. find the actual length of the surfboard if 1/2 inch length on the drawing corresponds to 3/8 foot of actual length.

3/8 of a foot = 3/8 x 12/1  or 4  1/2 inches

So our 1/2 inch grows by a factor of 9  because 4 1/2 ÷ 1/2 = 9  Think how many 1/2 dollars are in 4  1/2 dollars.  (Answer is 9)

So our 8 4/9 in the catalog has to grow the same

8  4/9   x 9  = 8  4/9  x 9/1 = 76/9 x 9/1  or 76 inches which is 6 ft 4 inches.
(76 ÷12 = 6 r4)

(-0, -7) is your answer