for intersecting lines,vertically opposite angles are equal
We can see two lines AB and DC in black color. We can freely move these four points A, B, C and D. Angle AED(α) and angle BEC(β) are also written. Move the points A, B, C and D and observe how the angles get changed.
Questions to think about 1. Compare the values of α and β, what do we observe? 2. Is it possible to get α≠β?