We are given the sides are congruent due to the tickmarks. Specifically
TU = WV (single tickmarks)
TV = WX (double tickmarks)
So we just need the "A" of "SAS". The A is between the two S letters, so the angle is between the two sides. For triangle TUV, the angle T is between the two sides with the tickmarks. Similarly, angle W is between the tickmarked sides of triangle WVX.
If we know that angle T = angle W, then we have enough information to use SAS.
