9. During a certain period in the life of an earthworm, its length, L cm, is directly proportional to the square root of N, where N is the number of hours after its birth. One hour after an earthworm is born, its length is 2.5 cm. 0 Find an equation connecting L and N. (ii) Find the length of an earthworm 4 hours after its birth. (iii) How long will it take for an earthworm to grow to a length of 15 cm?