Question:
State SAS similarity criterion.
Solution:
SAS Similarity Criterion: If in two triangles, one pair of corresponding sides are proportional and the included angles are equal then two triangles are similar.
In ΔABC and ΔDEF, if
$\frac{\mathrm{AB}}{\mathrm{DE}}=\frac{\mathrm{AC}}{\mathrm{DF}}$ and
$\angle \mathrm{A}=\angle \mathrm{D}$
Then, $\triangle \mathrm{ABC} \sim \triangle \mathrm{DEF}$