Complete the explanation, which explains why the triangles are congruent by using the ASA Triangle Congruence Theorem . Overline HJ cong overline QR (both are units long) . ? The triangles are congruent by the ASA Triangle Congruence Theorem. Complete the explanation , which explains why the triangles are congruent by using rigid motions . You can map triangle GHJ onto triangle POR by a translation ? Followed by a reflection across the ? By the definition of congruence in terms of rigid motions, the triangles must be congruent .