Negative and Positive numbers dictate direction on a graph. Negative numbers indicate the point is moving left, and positive numbers indicate the point is moving right.
Since the problem is to prove that the two triangles are congruent by applying SSS (side -side -side) congruence theorem, the missing or the additional information that can be shown in the solution is the third side of both triangles must be also equal and congruent. Since in SSS theorem, all sides of a given triangle must be congruent to the opposite three sides of the second triangle.
