1. Angles of Triangles
Chapter 4-2
DNA

2. Triangle Sum Theorem mA + mB + mC = 180o
The measures of the s of a  add up to 180o A B C
mA + mB + mC = 180o

3. Triangle Sum Theorem 7x + 2 + 8x – 3 + 5x + 1 = 180 20x = 180 x = 9
Check your answer!!!
7(9) (9) – (9) + 1 –
= 180

4. A.
A. 95
B. 75
C. 67
D. 85 A B C D
Lesson 2 CYP1

5. B.
A. 95
B. 75
C. 105
D. 85 A B C D
Lesson 2 CYP1

6. C.
A. 48
B. 75
C. 57
D. 67 A B C D
Lesson 2 CYP1

7. x + y + z = 180
 Sum Theorem
a + z = 180
Linear Pair Theorem
x + y + z = a + z
Trans. Prop. = x
x + y = a
Subtraction Prop. = y z a

8. Exterior Angle Theorem
An exterior angle of a triangle is equal to the sum of the two non-adjacent angles of the triangle. x
ma = mx + my a y

9. Exterior Angle Theorem
11x – 7 = 4x x – 2
11x – 7 = 10x + 3
x = 10

10. A. 50
B. 45
C. 120
D. 130 A. A B C D
Lesson 2 CYP2

11. A. 50
B. 45
C. 120
D. 130 B. A B C D
Lesson 2 CYP2

12. A. 85
B. 135
C. 45
D. 75 C. A B C D
Lesson 2 CYP2

13. A. 75
B. 45
C. 55
D. 85 D. A B C D
Lesson 2 CYP2

14. A. 130
B. 150
C. 140
D. 120 E. A B C D
Lesson 2 CYP2

15. The piece of quilt fabric is in the shape of a right triangle
The piece of quilt fabric is in the shape of a right triangle. Find mA if mC is 62.
A. 62
B. 28
C. 38
D. 152 A B C D
Lesson 2 CYP3

16. Homework:
Pg 214
# 1 – 7, 9 – 22, 37, & 39