The actual dimension of the sail are 6 m tall and 4.5 m wide.
The model is 20 cm tall. First we need to find the ratio which Kendall used in his model.
6 meters of actual length is represented in model by 20 cm.
6 meters of actual length is represented in the model by 0.2 m.
1 meter of actual length is represented in the model by 0.2/6 = 1/30 meters
So, the ratio of actual measure to model measure will be:
1 : 1/30
or
30 : 1
The actual width of the sail = 4.5 meters
The width of the sail in the model will be = 4.5 x 1/30 = 0.15 m = 15cm
So, the dimensions of the sail in the model will be 20 cm tall and 15 cm wide.