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.

(N/A) In $\triangle ABC$ and $\triangle QRP$:
$\frac{AB}{QR} = \frac{2}{4} = \frac{1}{2}$
$\frac{BC}{RP} = \frac{2.5}{5} = \frac{1}{2}$
$\frac{AC}{QP} = \frac{3}{6} = \frac{1}{2}$
Since the ratios of the corresponding sides are equal,by the $SSS$ (Side-Side-Side) similarity criterion,the triangles are similar.
Therefore,$\triangle ABC \sim \triangle QRP$.