1) Use the CIRCLE WITH CENTER THROUGH POINT [icon]/images/ggb/toolbar/mode_circle2.png[/icon] tool to construct a circle with center [i]A[/i] that [br] passes through [i]B[/i]. [br][br]2) Select the POINT ON OBJECT [icon]/images/ggb/toolbar/mode_pointonobject.png[/icon] tool. With this tool selected, touch the circle in 2 different spots [br] to plot two different points, [i]C[/i] and [i]D[/i], on the circle itself. [br][br]3) Use the POLYGON [icon]/images/ggb/toolbar/mode_polygon.png[/icon] tool to construct the triangle [i]ACD[/i]. [br] How would you classify this triangle by its sides? Why is this? [br][br]4) Select the MOVE [icon]/images/ggb/toolbar/mode_move.png[/icon] tool. Now touch one blue segment that serves as a side of this triangle. [br] In the style bar that appears, select the "Aa" icon. Check "Value" to show the length of this segment. [br] Repeat this action for the other 2 sides as well. [br][br]5) Use the ANGLE [icon]/images/ggb/toolbar/mode_angle.png[/icon] tool to find and display the measures of all 3 angles of this triangle.
What do you notice? (Be sure to select the MOVE tool again and move all 4 points around!) [br]
[i]If 2 sides of a triangle are congruent, then the angles opposite those sides are congruent.[br][/i][br][b]Teachers:[/b][br]This is one powerful means for students to actively discover Isosceles Triangle Theorem for themselves!
[color=#0000ff]When you're done (or if you're unsure of something), feel free to check by watching the quick silent screencast below the applet. [/color]