Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum

Monthly Update sign up
Mailing List signup
Search
Follow The Annenberg Learner on LinkedIn Follow The Annenberg Learner on Facebook Follow Annenberg Learner on Twitter
MENU
Learning Math Home
Session 5: Notes
 
Session 5 Part A Part B Part C Homework
 
Glossary
Algebra Site Map
Session 5 Materials:
Notes
 

B C 

Solutions
Video

Notes for Session 5, Part C


Note 4

If you are working in a group, check to see if anyone used a cutting method similar to the one presented here. If so, consider using their method to launch the proof rather than the one shown here.

<< back to Part C: The Midline Theorem


 

Note 5

Spend a few minutes reflecting on or discussing each fact. If you are working in a group, it may help to have posters of these that everyone can refer to as they work on the proofs.

<< back to Part C: The Midline Theorem


 

Note 6

It's sometimes hard for people to separate this figure from the cutting activities they've just been engaged with. Make sure you're clear about how the figure was constructed; it might help to create it yourself. First, start with the triangle. Find midpoints D and E and connect them. Then extend that segment to twice its length. Recall what we know: AD = DC (D is a midpoint); BE = EC (E is a midpoint); DE = EF (we made the figure that way); angle DEF is 180° (we made it a straight line). That's all we know.

<< back to Part C: The Midline Theorem


 

Note 7

You may have already made a conjecture about this situation in the Take It Further section of Session 4. Now you have the tools to actually prove it.

<< back to Part C: The Midline Theorem

 

Learning Math Home | Geometry Home | Glossary | Map | ©

Session 5 | Notes | Solutions | Video

© Annenberg Foundation 2014. All rights reserved. Legal Policy