[math]\overline{DE}[/math] is a mid-segment. What are the endpoints of a mid-segment?
The endpoints of the Mid-Segment are the midpoints of two sides.
What looks to be true about [math]\overline{AC}[/math] & [math]\overline{DE}[/math]?
[math]\overline{AC}[/math] is double the length of [math]\overline{DE}[/math].
What looks to be true [math]\angle A[/math]&[math]\angle BDE[/math]?
[math]\angle A[/math] & [math]\angle BDE[/math] are corresponding angles, knowing what you know from the question above, what can we say about [math]\overline{DE}[/math]&[math]\overline{AC}[/math]?
Move the applet, Does everything look to be always true?
Good, So you will use what you just learned on the homework?