we can see that the two triangles share an angle and all their sides are parallel, thus by Tales theorem, they are in Tales position, which proves that they are congruent.
we can see from figure that:
call x and y the unknown segments TA and TN, then we have:
3.3/(3.3 + x) = 6/8
8*3.3 = 6(3.3 + x)
x = 1.1
and then the proportion still holds for those sides as well as AN and RI
we also have:
y/(y + 1.6) = 6/8
8y = 6y + 9.6
y = 4.8
and then the proportion still holds for those sides as well as AN and RI
