hi all attached is a question and answer from an exam paper which i am having trouble with.

firstly i do not see how they can state the ASA rule without further information.

secondly i would have drawn the perpendicular bisector of line YZ and labelled the point of intersection with YZ as W then stated

YW = WZ (common)

XW (common)

XY=XY (given XYZ isoscles triangle)

therefore triangle congruent SSS

any ideas please?