A car leaves an intersection traveling west. Its position 4 sec later is 22 ft from the intersection. At the same time, another car leaves the same intersection heading north so that its position 4 sec later is 29 ft from the intersection. If the speeds of the cars at that instant of time are 7 ft/sec and 13 ft/sec, respectively, find the rate at which the distance between the two cars is changing. (Round your answer to one decimal place.)