Answer:
DC = 17
Explanations:
From the diagram shown:
DE is symmetrical to BE
DE = BE
AD = 11
BC = 17
ADE and BAE are congruent triangles because :
DE is congruent to BE and
AE is shared by both.
Also angle E is a right angle in both
This is called the SIde-Angle -Side Property (SAS)
Therefore, BC = DC = 17