Classifying Triangles by Sides-part 1

Isosceles Triangle
In the applet below, you can drag the slider to enlarge the triangle. You can also drag points B and C to see other variations.
Isosceles
Isosceles Triangle
After playing with the applet, what is it about the sides of a triangle that would allow it to be classified as isosceles?
Isosceles Triangle
Although angles are not the focus right now, there is something cool about the angles of an isosceles triangle. What is it?
Notes
Don't forget to record your findings on your notes page.

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