Circle with diameter and extra point
Instructions
1) Use the "Polygon" tool to create ΔBCD
2) Use the "Angle" tool to measure all three angles of the triangle
3) Use the "Distance or Length" tool to measure all three sides of the triangle
4) Draw segment AD
5) Use the "Distance or Length" tool to measure segments BD, DC, CB and AD. You will need to select the endpoints of each segment in order to find the lengths
6) Move point D along the circle, and see if you notice any invariants