Friday, January 09, 2009
Geometry (Class 41)
Announcements
Test Wed. 12/17 focusing on proving lines parallel.
Lesson Title
Constructions 3.5
Overview
The warm-up today asks students to determine the needed length for a missing side, or sides, of a triangle in order for the triangle to turn out to be a specific type. For instance, if two sides of a triangle were 3 cm and 5 cm, what could be the length of the third side so that the triangle was a right triangle?
The lesson for today will focus on developing student’s problem solving skills.
Textbook Sections
§5.5 (txt. p.295) Inequalities in One Triangle
Vocabulary
construction
straight edge
arc
radius
center
diameter
Key Attitudes
Math is about being convinced a statement is always true.
Key Ideas
A straight edge and compass can be used to create geometric figures.
A compass is used to measuring lengths by making circles and arcs.
Some parts of a construction can be places wherever you want, while others have to be determined.
If you want a line to be in a specific location, then you have to have two points that it goes through. These points can be created by the intersection of two lines, two arcs, or a line and an arc.
It is not possible to construct a triangle out of just any three line segments!
Key Skills
I can construct a triangle from three line segmetns.
I can determine if it is possible to construct a triangle when given three line segments, or the lengths of three line segments.
I can determine the possible lengths for the third side of a triangle when given the lengths of two of the triangles sides.
Turn-In (#40)
Finish “Constructions 3”
Chapter 3 Practice: Proving Lines Parallel All
Handouts
Constructions 3.5
Assignment
Finish Constructions 3.5
Disclaimer- The assignment as stated in class is the official assignment. Every effort is made to keep this posting accurate, but you should refer to what was stated in class as the final word.
Permalink