Question 1071211
The sides of the smaller triangle are {{{12/18=2/3}}} as long
as the corresponding sides of the larger triangle.
When similar shapes have corresponding length different by a factor {{{k}}} ,
the surface areas are different by a factor {{{k^2}}} .
It does not matter if the shapes are squares, triangles circles, or odd shapes,
as long as they are the same scrape scaled up of down by a factor {{{k}}} .
So, the area of the small triangle is {{{(2/3)^2=4/9}}}
of the area of the large triangle.
The area of the small triangle is {{{(4/9)*(36ft^2)=highlight(16ft^2)}}} .