5.1 midsegments.notebook
10/27/16 - Warm Up Problem
Find the slope of each line.
Are the lines parallel, perpendicular, or neither?
Line 1: (-2, 4) and (3, 14)
Line2: (0, -3) and (3, 3)
October 27, 2016
5.1 midsegments.notebook
October 27, 2016
Section 5.1 - Midsegment Theorem
Goal: identify and use properties of midsegments
Hands on Activity:
1. Draw a large triangle - use a straight edge
Cut out the triangle
2. Classify your triangle
- scalene, isosceles, equilateral
- acute, obtuse, right, equiangular
3. Label the vertices A, B, and C
4. Fold A onto C to find the midpoint of AC.
Fold B onto C to find the midpoint of BC.
5. Label the midpoints L and N,
then draw in LN.
• How does LN appear to be related to AB?
5.1 midsegments.notebook
October 27, 2016
6. Fold your triangle along LN.
7. Fold A to C. Fold B to C.
• Make a conjecture about how the length
of LN compares to AB?
5.1 midsegments.notebook
October 27, 2016
Midsegment of a Triangle: a segment that connects the
midpoints of two sides of the triangle
Theorem 5.1 - Midsegment Theorem
If a segment joins the midpoints of two sides of a
triangle, then the segment is _________ to the third
side and __________________.
A
10
B
E
12
D
26
C
5.1 midsegments.notebook
October 27, 2016
Find the value of x.
9
3x + 6
5.1 midsegments.notebook
Assignment:
pg. 288
(7-25)
October 27, 2016