13.
arc AB=arc BC ( given in question) and it is a side.
angle ABC=angle BCD ( both are right angle) and it is an angle.
arc BC = arc BS(common sides in two triangle) and it is a side.
Hence triangleABC is cocurent to triangle BCD by
SAS axiom.
14.
If you look closer
angle ACB=angle DCE as they are vertically opposite to each other
so,
in triangle ABC and CDE,
angle ABC=angle DCE ( being vertically opposite angles)
BC =CD ( it is given in question)
angle ABC= angle CDE( since two angles of two triangles are equal, the third angles are also equal)
Hence triangle ABC is congurent to triangle CDE by
ASA axiom
