We are unable to see your diagram, but the mainsail has the shape of a right triangle. So, we can conclude that the hypotenuse is 14', the upright is 11', and the base is 5'.
We can then use simple proportion to determine the dimensions of the sail model, which would result in a base of 2', an upright of 4.4', and an hypotenuse of 5.6'
Using the base and upright, we can write 5' :: 11' = 2" :: x, and solve for x.
The same idea can used for the other dimensions.