SWBAT: Apply theorems about the interior and exterior angles of triangles.
Exterior
angles of a
triangle
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Warm Up #1 (page 8)
Find the measure of the missing angles.
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Warm Up #2 (page 8)
Let x = Smallest Angle = 31˚
= 93˚
3x= 2nd Angle
x+25 = 3rd angle
= 56˚
x + 3x + (x+25) = 180˚
5x + 25 = 180˚
5x = 155˚
x = 31˚
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Warm Up #2 (page 8)
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Homework (page 6-7)
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Homework (page 6-7)
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Homework (page 6-7)
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Homework (page 6-7)
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Part 1: (page 9)
Angle relationships in triangles. Find the measure of all angles in the triangles
below. Then answer the following questions and try to develop the theorems
that represent these relationships. After checking the theorems with your
teacher, then complete the remaining examples.
47°
133°
∡𝟏 = 𝟏𝟖𝟎° − (𝟕𝟏0 + 𝟔𝟐0 )
∡𝟐 = 𝟏𝟖𝟎° − (𝟒𝟕⁰)
∡𝟏 𝐚𝐧𝐝 ∡𝟐 𝐚𝐫𝐞 𝐚 𝐥𝐢𝐧𝐞𝐚𝐫 𝐩𝐚𝐢𝐫
(Supplementary)
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Part 1: (page 9)
130°
50°
53°
90°
∡𝟏 + 𝟑𝟕° = 𝟗𝟎0
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Part 2: Conclusions (page 10)
Investigate the Triangle Sum Theorem and its corollaries
47°
180°
130° 180°
53°
180°
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Part 2: Conclusions (page 10)
Investigate the Triangle Sum Theorem and its corollaries
180°
Sum to 90°
60°
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Part 2: Conclusions (page 10)
Investigate the Exterior Angles Theorem
133°
133°
50°
50°
53°
90°
90°
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Part 2: Conclusions (page 10)
Investigate the Exterior Angles Theorem
The exterior is equal to the sum of the
two non adjacent interior angles.
a
b
x
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Part 3: Practice (page 11)
Apply the new theorems to solve each problem.
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Part 3: Practice (page 11)
Apply the new theorems to solve each problem.
∡PRS
9x+2
9(5)+2
47⁰
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Summary (page 12)
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Exit Ticket (page 12)
∡EFH
8x+8
8(13)+8
112⁰
8x + 8 = (3x-3) + 76˚
8x + 8 = 3x + 73
8x = 3x + 65
5x = 65
x = 13
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
Challenge (page 12)
Use the information given in the diagram to determine the m∡ACB.
B
4x+3
2x2+3x-2
x2+1
A
C
D
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15
SWBAT: Apply theorems about the interior and exterior angles of triangles.
HW pg 13-15