Question:
State AAA similarity criterion.
Solution:
AAA Similarity Criterion: If two triangles are equiangular, then they are similar.
In ΔABC and ΔDEF, if
$\angle \mathrm{A}=\angle \mathrm{D}$
$\angle \mathrm{B}=\angle \mathrm{E}$
$\angle \mathrm{C}=\angle \mathrm{F}$
Then, $\triangle \mathrm{ABC} \sim \triangle \mathrm{DEF}$