Step-by-step explanation:
when scaling a model or a map or ... there is airways the same scaling factor applied for every dimension of the object.
in other words, length and width of the plane must be multiplied by the same factor.
the length is first scaled by going from feet to inches. and then scaled by the factor 1/2, as 27/2 = 13.5.
we need to do the same for the width. feet to inches and then half : 18/2 = 9 in