This document provides instructions for a lesson on midsegments in triangles. It defines what a midsegment is, notes that triangles have three midsegments, and outlines a lab for students to complete in groups to learn about the midsegment theorem. The theorem states that the segment connecting the midpoints of two sides of a triangle is parallel to the third side and is half as long. The document includes example problems for students to practice applying the midsegment theorem.

1. Midsegment
in triangles
MR. SAUCEDO
GEOMETRY
MILBY HIGH SCHOOL

2. OBJECTIVE
To find measurements of triangles using its
midsegments.

3. WHAT IS A MIDSEGMENT?

4. A TRIANGLE HAS 3 MIDSEGMENTS

5. MIDSEGMENT LAB
Work in groups of 4
You will have 25 minutes to complete lab.

6. MIDSEGMENT THEOREM
Definition:

The segment connecting the midpoints of two sides of a
triangle is parallel to the third side and is half as long as that
side.
VISUAL:

7. CHECKPOINT
All lines inside triangle ABC are midsegments.
1. What is the midsegment of AB: ______
2. Line FE is parallel to _____
3. Line FD is parallel to _____
4. Line DE is parallel to _____
5. If FE = 5, then AB= ____
6. If FD=10, then CE= ____
7. If AB=30, then FE= ____
8. If CA=12, then DE=_____

8. GUIDED EXAMPLE
If MP=2x-1, and BC=3x+5, what is MP and BC?

9. If AD= 2x+4 and DB=3x-1, what is FE?

10. INDEPENDENT PRACTICE

11. HOMEWORK
Section 5.1, page 8-86
Problems 1 – 9, 15
Pre AP: Add problem 19