State which pairs of triangles in the figure are similar. Write the similarity criterion used by you for answering the question and also write the pairs of similar triangles in the symbolic form.

(NONE) In $\triangle ABC$ and $\triangle DEF$:
Given $\angle A = 80^{\circ}$ and $\angle F = 80^{\circ}$.
Also,the sides including these angles are:
$AB = 2.5$,$AC$ is not given.
$DF = 5$,$EF = 6$.
Checking the ratio of sides:
$\frac{AB}{DF} = \frac{2.5}{5} = \frac{1}{2} = 0.5$
$\frac{BC}{EF} = \frac{3}{6} = \frac{1}{2} = 0.5$
Since the ratio of two sides is equal and the included angle is not the same (the angle $80^{\circ}$ is at $A$ in $\triangle ABC$ and at $F$ in $\triangle DEF$),the triangles are not similar by the $SAS$ criterion.
Therefore,the given triangles are not similar.