1. Pre-Algebra
Lesson 7.6
Triangles

2. Whadda ya know 'bout...
Triangles

4. Review: Degrees of Angels
angles
Acute
Right
Obtuse
Less than 90o
90o degrees
Greater than 90o

5. In every triangle, the sum of all the interior
angles equal up to ______ degrees.
A
C
B
C
B
A

7. Finding the measure of an unknown angle
45o
65o
1
65o + 45o + m∠1 = 180o
110o + m∠1 = 180o
m∠1 = 70o

8. Your turn:
What is m∠E?

9. Your turn:
What is m∠A?
A
88o
B
37o
C

10. Your turn:
What is x?
isosceles
x + x + 140o = 180o
138o

11. Types of triangles
Acute
Triangle
All 3 angles
are acute
Right
Triangle
Exactly one
angle is right
angles
Obtuse
Triangle
Exactly one
angle is obtuse

12. Classify these triangles

14. 1. Dealer, give two students 2 cards each, and one
student the missing angle card. **if no dealer,
everyone choose your own cards. Rotate missing
angle card.
13
57
?
2. Missing angle card: find out your degree.
13 + 57 + ? = 180
3. Known angles, figure out your degree.
4. Rotate. Take turns being dealer/missing angle