Solution
The Side-Angle-Side (SAS) Theorem states if two sides of one triangle are proportional to two corresponding sides of another triangle, and their corresponding included angles are congruent, the two triangles are similar.
Next
AC is corresponding to EC
BC is corresponding to DC
[tex]\begin{gathered} \frac{AC}{EC}\text{ = }\frac{6}{12}\text{ = }\frac{1}{2} \\ \frac{BC}{DC}\text{ = }\frac{5}{10}\text{ = }\frac{1}{2} \end{gathered}[/tex]
The ratio of their corresponding sides is proportional.
Final answer
The Side-Angle-Side (SAS) Theorem
