Answer:
Refer to the attachment for the labelling of the triangles.
In △ABC & △DEC,
∠C = ∠C [common angles → vertically opposite angles]
AC = CE [equal pair of sides]
BC = DC [equal pair of sides]
•°• △ABC ≅ △EDC (Single-Angle-Side congruence rule → SAS congruence rule.....the angle is included between the 2 equal sides).
Hope it helps ⚜
