Iknow the answer but how do i get it ?

How are sas and sss used to show that two triangles are congruent?

:)i need to know on which ones are corresponding, alternate interior, alternate exterior, or none of these.

Question 2 (essay worth 10 points) (03.02 mc) in δabc shown below, point a is at (0, 0), point b is at (x2, 0), point c is at (x1, y1), point d is at x sub 1 over 2, y sub 1 over 2, and point e is at the quantity of x sub 1 plus x sub 2 over 2, y sub 1 over 2: triangle abc is shown. point d lies on segment ac and point e lies on segment bc. a segment is drawn between points d and e. point a is at the origin. prove that segment de is parallel to segment ab.