Here, we want to proof that the two triangles are congruent
a) Statement 1
YX = ZX
Reason 1
Given
b) Statement 2
angle WXZ = angle WXY
Reason 2
Given that WX bisects angle YXZ, the two angles are equal
c) Statement 3
WX = WX
Reason 3
Reflexive property of equality
d) Statement 4
Triangle WYX is congruent to Triangle WZX
Reason 4
Side-angle-side SAS