Google Classroom
GeoGebraGeoGebra Classroom

Three tangents

Author:
Idan Tal
The appletillustrates thatvariance of the location of point D on the arc BC does not change the perimeter of triangle AEF (invariance). This property exists for any size of the circle (drag point O), or for any external point A to the circle (drag point A, and then check for changing the location of D on the arc BC).