1. 1) Place binder and text on desk. 2) Do review handout - parallel line
Geometry November 2012
1) Place binder and text on desk.
2) Do review handout
- parallel line
angle relationships
3) Do back
-marking corresponding
congruencies

2. Congruent Figures For the triangles below, ∆ABC ≅ ∆PQR
The notation shows congruence and correspondence.
When writing congruence statements, be sure to list corresponding angles in the same order. A B C
Corresponding Angles
Corresponding Sides
A ≅ P
AB ≅ PQ
B ≅ Q
BC ≅ QR
C ≅ R
CA ≅ RP P Q R

3. Objective
Students will explore and apply triangle sum and properties of isosceles triangles to find missing angle measures. Students will take notes, do an investigation and use think-pair-share as they solve problems. Homework due TUESDAY: 4.2, page 208: 6 – 10, 18 – , page 217+: Investigation 2 show all steps write the conjecture

4. Strategies for problem solving:
1) Mark everything you KNOW on the diagram parallel line conjectures: AIA, AEA, CA, SSIA LP and VA conjectures triangle sum conjecture 2) use COLOR to mark congruent parts, parallel lines, etc.

5. you may NOT assume that:
lines are parallel unless they are marked or have angle measures indicating they are parallel
lines ARE perpendicular unless they are marked or angle measures indicate they are
pairs of angles, segments, polygons are congruent unless they are marked with information that shows you that they are

6. Isosceles Triangle vocabulary, pg. 206
Legs
Base Angles
Vertex Angle

7. If the base angles are congruent, do we KNOW the triangle IS ISOSCELES?
converse = ? Check your notes
Switch the If…. and then…. parts
CONVERSE: If a triangle has two congruent angles,
the it is an isosceles triangle.
Demonstration-- Investigation 2- page 208

8. Chapter 4 Triangles Definition Triangle Sum Conjecture
Term
Definition
Example
Triangle Sum Conjecture
The sum of the measures of the angles in every triangle is
1800
x + y + z = 180⁰
Isosceles triangle conjecture
If a triangle is isosceles, then its base angles are congruent
Converse of Isosceles
Conjecture
If a triangle has two congruent angles, then it is an isosceles triangle.

9. vocabulary Congruent– same shape AND size
Similar– same shape but not necessarily same size
INCLUDED ANGLE
The angle between
two given sides.
INCLUDED SIDE
The side between
two given angles included side
between ⦟A and ⦟B
included angle
between and C A B

10. Practice Handout 4.1 and 4.2
1) EVERYBODY work with your group to do 4.1: # 1, 2, 3, 6, 7 and 8 AND 4.2: ALL STUDENTS need to do all these problems 2) GROUP assignments Groups 1 and 5: 4.1: # 4 4.2: #6 Groups 2 and 6: 4.1: #10 4.2: #9 Groups 3 and 7: 4.1: # : #8 Groups 4 and 8: 4.1: # 9 4.2: #10 CHOOSE- white board or poster paper

11. Debrief
what did you learn today? what is still confusing? what is easy?