Side-Angle-Side Theorem states that triangles are congruent if any pair of corresponding sides and their included angle are congruent.
How do we know that their sides are congruent, by similarity ratios, means a ratio of the lengths of the sides to see if they have the same ratio or scale factor:
[tex]\begin{gathered} \frac{9}{6}=1.5 \\ \frac{6}{4}=1.5 \end{gathered}[/tex]
Then, since their sides are congruent and they have the same angle, they are congruent by SAS.
