Midsegment: A segment connecting the midpoints of 2 sides of a triangle.
Thm 4-8: TRIANGLE MIDSEGMENT THM: If a segment joins the midpoints of 2 sides of a triangle, then the segment is paralllel to the 3rd side and 1/2 its length.
If a segment doesn't join the midpoints of 2 sides of the triangle, what is it not?