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TRIANGLES
Chapter 5
Guess What we will learn about
1
Geometry Unit Properties of Triangles
Objectives:
Review:
Linear expressions
Absolute Values
Inequalities
Triangles
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IN CLASS
Algebra Review
Page 258
#’s 1, 3, 7, 12, 13, 22, 27, 29,
37, 49, 64, 66
Find the equation of the
line that is perpendicular to
the line y = 2/3(x) – 3 the
goes through the
coordinate (4, 6)
Page 256 #’s 1, 2, 4, 5, 6, 7
Unit 5 Lesson 1 Jan 4
DO NOW: Get out your
SUMMARY SHEET.
Given the coordinates
A= (3, 4) B= (8, 4)
What is the length of AB?
What is the Equation for AB?
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Geometry Unit Properties of Triangles
Unit 5 Lesson 1
HOMEWORK
Page 258:
#’s 2, 5, 9, 15, 16, 25,
27, 39,65
Find the equation of
the line that is parallel
to the line y = 2/3(x) – 3
the goes through the
coordinate (4, 6)
Page 256 #’s 1, 2, 4, 5,
6, 7
2
Objectives:
-Concurrency
-Median
-Altitude
-Perpendicular Bisectors
-Circumcenter
-Centroid
-Incenter
-Orthocenter
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IN CLASS
Triangle Bisectors
Page 275 -276: #’s 6 – 18 even
Unit 5 Lesson 2 HOMEWORK
Triangle Bisectors
Page 275 -276: #’s 5 – 19 ODD
20- 22, 24 – 28
Honors 32 – 40
Geometry Unit Properties of Triangles
Unit 5 Lesson 2 Jan 9
DO NOW:
Page 268:
#9
Find and draw example
of 5 vocab words for 5.2
 Unit
5 Lesson 2
HOMEWORK
 Triangle Bisectors
 Page 275 -276:
 #’s 5 – 19 ODD
 20- 22, 24 – 28
 Honors 32 – 40
3
4
Unit 5 Lesson 2 Jan 9
Point of Concurrency
Intersection of three or more lines or line segments
Angle bisectors
intersect at the In-center
Median Centroid
Goes from the vertex to midpoint on
the opposite side of the triangle
Perpendicular Bisectors Circumcenter
A perpendicular line that divides a
segment in half
In-center
The point of concurrency that is
formed by the angle bisectors of a
triangle
Centroid
The center of gravity; the point of
concurrency that is formed by the
medians of a triangle
Altitude Orthocenter
Perpendicular line that goes
through the vertex to the opposite
side or the line containing the
opposite side
Circumcenter
The point of concurrency that is
formed by the perpendicular
bisectors of a triangle
Orthocenter
The point of concurrency that is
formed by the altitudes of a
triangle.
Geometry Unit Properties of Triangles
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5
Unit 5 Lesson 2 Jan 9
Geometry Unit Properties of Triangles
Objectives: 5.3
-Triangle Medians and Altitudes
-Be able to find ALL missing sides and
angles using centroids and
Orthocenters
CLASS
 Page 311
 #’s 6,7,8,9
 Page 282 – 284 :
 #’s 1 – 7 ALL
Unit 5 Lesson 3 Jan 12
DO NOW:
Page 310 # 4
 IN
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Geometry Unit Properties of Triangles
Unit 5 Lesson 3
HOMEWORK
Triangle Medians and
Altitudes
Page 311
#’s 6,7,8,9
Page 282 – 284 :
#’s 1 – 7 ALL
6
Objectives: 5.3
- Review
Unit 5 Lesson 4 Jan 13
DO NOW:
Find the coordinates of
the centroid if:
A=(0, 0)
B =(4, 10)
C =( 8, 2)
 IN
CLASS
 Page 310 – 311
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Create a summary sheet
 HANDOUT
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TEST your summary Sheet
Geometry Unit Properties of Triangles
 Unit
5 Lesson 4
HOMEWORK
 Complete handout
7
Objectives: 5.3
- Triangle Medians and Altitudes
- Review Distance Formula
- Review midpoint Formula
- Be able to find ALL
missing sides
and angles
using Centroids and Orthocenters
CLASS
 Page 282 – 284 :
 #’s 8 – 12 ALL
Unit 5 Lesson 5 Jan 14
DO NOW:
Find the coordinates of
the centroid if:
A=(0, 0)
B =(4, 10)
C =( 8, 2)
 IN
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Geometry Unit Properties of Triangles
Unit 5 Lesson 5
HOMEWORK
Triangle Medians and
Altitudes
Page 282 – 284 :
#’s 13 – 16 all
#’s 17 – 20 all
#’s 21, 22, 23l
39 – 45
HONORS: 35, 36
8
Objectives: 5.4
-Utilize Mid-Points to find
Mid-segments
-Create a Mid-segment Triangle
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CLASS:
Page 287 Example 1
Page 289 Example 4
Page 290 #’s 1 – 11 ALL
Geometry Unit Properties of Triangles
Unit 5 Lesson 6 Jan 17
DO NOW:
If A = (2, 0) B = (0, 2)
-Find the midpoint
between AB
-Find the Distance
between AB
 Unit
5 Lesson 6
HOMEWORK
 Page 290- 291:
 #’s 12 – 18 all, 21- 25 all
9
Objectives: 5.5
Finding the longest and shortest sides of a
Triangle
Triangle sides:
Side1 + Side2 > Missing
Side1 + Missing > Side2
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IN CLASS
Page 297 Example 3 / 4
Unit 5 Lesson 7 Jan 19
DO NOW: If A = ( 0, 0)
B= (10, 4) & C= (2,8)
Find the midsegment of
AC and BC
Do the line segments
4 , 7, 8 make a triangle?
-What are the possible
lengths of the missing side
of a triangle if two of the
sides are: 4 & 7?
Page 298- 299:
#’s 1 – 5 all
# 7 – 15 odd
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Geometry Unit Properties of Triangles
Unit 5 Lesson 7 HOMEWORK
Finding the longest and
shortest sides of a Triangle
Page 298- 299:
#’s 6 – 22 ALL
#’s 24 – 37 ALL
39 – 46 ODD
Honors 38
10
Unit 5 Lesson 8 Jan 20
Objectives:
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DO NOW: What are the
possible lengths of a
missing side when 2
sides given are 8 & 9?
IN CLASS
Q page 293
#’s 39 – 49 odd, 50, 51, 53
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Geometry Unit Properties of Triangles
Unit 5 Lesson 8
HOMEWORK
Indirect Proofs
Page 305 – 307:
#’s 7 – 27 ODD
Page 308 Quiz 2
#’s 1 – 8 All
HONORS: 38 - 42
11
Objectives:
Review for Unit 5
Triangle TEST
DO NOW:
 IN
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CLASS
Practice Test
Unit 5 Lesson 9 Jan 23
Geometry Unit Properties of Triangles
 Unit
5 Lesson 9
HOMEWORK
 Finalize Summary Sheet
12
Objectives:
Unit 5 assessment
Unit 5 Lesson 10 Jan 24
DO NOW: Test
 IN
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CLASS
TEST
 Unit
5 Lesson 10
HOMEWORK
 Write out and define ALL
20 vocabulary words and
terms found in chapter 6
review Page 382
Geometry Unit Properties of Triangles
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