1. Objective: To use the properties of midsegments to solve problems.
Chapter 5 Lesson 1
Objective: To use the properties of midsegments to solve problems.

2. Midsegment
In ∆ABC above,     is a triangle midsegment. A midsegment of a triangle is a segment connecting the midpoints of two sides.

3. Theorem 5-1 Triangle Midsegment Theorem
If a segment joins the midpoints of two sides of a triangle, then the segment is parallel to the third side, and is half its length.

4. Example 1: Finding Lengths
In ∆EFG, H, J, and K are midpoints. Find HJ, JK, and FG.
HJ = ½ EG
HJ = ½ (100)
HJ = 50
HK = ½ FG
40 = ½ FG
JK = ½ FE
80 = FG
JK = ½ (60)
JK = 30

5. Example 2: Finding Lengths
AB = 10 and CD = 18. Find EB, BC, and AC.
EB = ½ DC
EB = ½ (18)
EB = 9
BC=AB
AC=AB+BC
BC=10
AC=10+10
AC=20

6. Example 3: Identifying Parallel Segments
In ∆DEF, A, B, and C are midpoints. Name pairs of parallel segments.
AC EF
BC ED
AB DF

7. Assignment
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