SOLUTION
Given
[tex]\begin{gathered} \nabla ABE \\ \text{And} \\ \nabla ACE \end{gathered}[/tex]
And
[tex]\begin{gathered} |BD|\cong|CD| \\ \text{and } \\ |BE|\cong|CE| \\ \text{Correspounding sides of a congruent triangles are congruent} \end{gathered}[/tex]
And looking at the common sides of the triangle
[tex]\begin{gathered} |DE|\cong|DE|\text{ are common sides of the} \\ \nabla DBE\text{ and }\nabla DCE \\ |DE|\cong|DE|\text{ . Reflexive} \end{gathered}[/tex]
Using the sides Angle Sides theorem of congruency: If two sides and the included angle of one triangle are equal to two sides and the included angle of another triangle, the triangles are congruent.
[tex]\begin{gathered} \Delta BDE\cong\Delta CDE \\ |DB|\cong|DC| \\ |DE|\cong|DE| \\ \text{Hence } \\ \angle BDE\cong\angle CDE \end{gathered}[/tex]
