These trianges are similar because they are both right triangles.
-7 is the answer ihope i heped
F varies directly with m ⇒ f/m =k ( this k remain the same )
when f=-19 and m=14 ⇒ k=f/m= - 19/14
when m=2 , f/m= - 19/14
f/2= -19/14
f= -2*19/14=-38/14= (-38:2)/(14:2) = - 19/7
⇒ f= -19/7