Answer:
Since it is a to-scale model,
the ratio of the wingspan to the length of both the airplanes must be equal
wingspan1 = 200 ft wingspan2 = 30 cm
length1 = 240 ft length2 = x cm
wingspan1 / length1 = wingspan2/length2
replacing the variables
200 / 240 = 30 / x
x = 30 * 240/200
x = 36 cm
Therefore, the length of Emma's airplane is 36 cm