Midpoint theorem in a triangle
1) Locate the midpoints D and E of [AB] and [AC] respectively.
2) Connect the two midpoints.
Compare the length of [BC] and the length of the segment connecting the midpoints. What do you notice?
Compare the angles ADE and ABC. What do you notice?
What can you conclude about (DE) and (BC)?
In conclusion, the line segment joining the midpoints of two sides in a triangle is equal to _________ and ___________ to the third side of the triangle