Google Classroom - Interaktiva lektioner
GeoGebraGeoGebra Classroom - Interaktiva lektioner

Exterior angle of a cyclic quadrilateral

On the screen, we see a circle with center A. A cyclic quadrilateral CDEF is drawn and one side FE is produced. Move the points A, B, C, D, E and F and observe how the angles DEG and FCD change.