To start, write your locations as points, with north and south being positive and negative y respectively and east and west being positive and negative x respectively. Doing this gives us the mall at (-3,-2) and the park at (4,5). Now, we use our distance formula 
to solve for the unknown distance. Plugging in with the park values as our second values and our mall values as our first values (as well as with our unknown distance as d), we get 
. This square root can be rounded to 9.9 miles.