Notice from the table that all three corresponding sides of the triangles CDA and BDA are congruent.
Recall the Side-Side-Side (SSS) Criterion:
It follows that the triangles CDA and BDA are congruent by the SSS criterion.
For the second congruence, it is shown that two pairs of corresponding sides triangles CED and BED are congruent, also a pair of included angles of the congruent sides are congruent.
Recall the Side-Angle-Side (SAS) Criterion:
It follows that the triangles CED and BED are congruent by the SAS criterion.