1. Triangles
Triangle: a figure formed when 3 noncollinear points are connected by segments.
Components of a triangle:
Vertices: A, B, C
Sides: AB, BC, AC
Angles: A, B, C

2. Triangles can be classified by Angles:
1) Acute - 3 acute angles
2) Obtuse - 1 obtuse angle
3) Right - 1 right angle

3. or Sides:
1) Scalene - no sides congruent
2) Isosceles - at least 2 sides congruent
3) Equilateral - all sides congruent

4. Focus on Isosceles Triangles
Vertex angle: the angle formed by the congruent sides C
Base: the side opposite the vertex angle
Legs: the two congruent sides
and
Base Angles: the two angles formed by the base and one of the congruent sides
 A and B

5. Application
Find d and the measure of each side of equilateral triangle KLM if
KL = d + 2
LM = 12 - d
KM = 4d - 13

8. Triangles on the Coordinate Plane
Classify RST by sides
R (-1, -3)
S (4, 4)
T (8, -1)

9. 1

10. 2

11. 3

12. 4

13. 5

14. 6

15. 7
Wednesday Worm

16. Homework

17. Homework