Not necessarily, because the premise is that two straight lines are parallel and the internal angles on the same side are complementary, and if they are not parallel, they are not necessarily complementary.

Junior high school mathematics congruence angle, internal dislocation angle, ipsilateral internal angle 24 Geometrically, ipsilateral internal angle, "ipsilateral" refers to the ipsilateral side of the third straight line; "Inside" means between two straight lines cut. Short note: the opposite corner. The sum of the two angles is 180, and the two straight lines are parallel.

The difference between congruent angle, internal angle and internal angle on the same side;

1, isomorphic angle feature: when two straight lines are cut by a third straight line, they are all in the same direction of the two straight lines, and the two angles on the same side of the cut line are isomorphic angles.

2. The characteristics of the internal angle: when two straight lines are cut by the third straight line, they are sandwiched inside the two straight lines, and the two angles on both sides of the cutting line are internal angles.

3. Characteristics of the inner angle on the same side: when two straight lines are cut by the third straight line, they are sandwiched between the two straight lines, and the two angles on the same side of the cutting line are the inner angles on the same side.