Below you will find a triangle. [br][br]1. Adust the triangle however you want. [br][list][*]Use the Move tool (the first tool) to move the points or the triangle.[/*][*]This is also the tool you would use to drag labels so they are easier to read.[/*][/list]2. Create a midpoint on one of the sides.[br][list][*]Select the Midpoint or Center tool (the 3rd tool) and click the desired side. (a new point should appear).[/*][/list]3. Create a new triangle by rotating the current one 180[math]^\circ[/math] about the midpoint you created.[br][list][*]Select the Rotate around Point tool (the sixth tool) and click the yellow part of the triangle, and then the new midpoint.[/*][*]A text box should pop up asking for the desired angle and direction. Input 180[math]^\circ[/math] and leave counterclockwise selected (Direction doesn't matter in this case). [/*][*]A new triangle should appear attached to the original one.[/*][/list]4. Add the angles to the new triangle.[br][list][*]Select the Angle tool (the fifth tool) and then click the yellow part of the new triangle.[/*][*]The three angles should appear (though they may look like [math]\epsilon=30^\circ[/math] just pay attention to the number).[/*][/list]5. Observe the lines and angles. Move the original triangle and see what happens. [br]