SSS (side-side-side) requires that all three sides of the potentially congruent triangles be congruent.
Triangle WVU & Triangle UBW are our two triangles.
The middle line, UW and WU are congruent by the reflexive property, so that is not the information we need to prove SSS.
For SSS, we need to know that sides WV and UB are congruent.
Hope this helps!
