Explanation:
because of the specific graphic presentation (the 2 triangles together create a kite) we have more than the written information about the triangles.
the written information tells us only about one pair of corresponding sides that are equivalent (TS and TU).
but due to the graphic we know, that the central side VT is shared 1:1 by both triangles. so, we know about a second pair of corresponding sides that are equal (equivalent) : VT.
and we know that these are right-angled triangles, so via Pythagoras we know that also the 3rd sides (SV and UV) must be equal (equivalent).
so, we know via SSS (side-side-side) that the two triangles are equivalent.