Answer: The wingspan is 36 m.
Using a proportion to solve this, we write the scale factor as a ratio first: 19/38, since 19 is the size of the model's length and 38 is the real length. For the second ratio, we have 18 for the size of the model wingspan and x for the real wingspan:
19/38 = 18/x
Cross multiply:
19*x = 38*18
19x = 684
I tried to make a list and found 27 ways
tell me if I missed any
order is
(3point,2point,1point)
(0,0,15)
(0,1,13)
(0,2,11)
(0,3,9)
(0,4,7)
(0,5,5)
(0,6,3)
(0,7,1)
(1,0,12)
(1,1,10)
(1,2,8)
(1,3,6)
(1,4,4)
(1,5,2)
(1,6,0)
(2,0,9)
(2,1,7)
(2,2,5)
(2,3,3)
(2,4,1)
(3,0,6)
(3,1,4)
(3,2,2)
(3,3,0)
(4,0,3)
(4,1,1)
(5,0,0)
27 is my answer