1. Lesson 5-1 Classifying Triangles

2. Ohio Content Standards:

3. Formally define geometric figures.

4. Ohio Content Standards: Establish the validity of conjectures about geometric objects, their properties and relationships by counter-example, inductive and deductive reasoning, and critiquing arguments made by others.

5. Ohio Content Standards: Make and test conjectures about characteristics and properties (e.g., sides, angles, symmetry) of two-dimensional figures and three-dimensional objects.

6. Triangle

7. A figure formed when three noncollinear points are connected by segments.

8. Acute Triangle

9. A triangle with all acute angles.

10. Obtuse Triangle

11. A triangle with one obtuse angle.

12. Right Triangle

13. A triangle with one right angle.

14. Scalene Triangle

15. A triangle with no sides congruent.

16. Isosceles Triangle

17. A triangle with at least two sides congruent.

18. Equilateral Triangle

19. A triangle with all sides congruent.

21. The angle formed by the congruent sides is called the vertex angle.

22. The side opposite the vertex angle is called the base.

23. The angle formed by the congruent sides is called the vertex angle. The side opposite the vertex angle is called the base. base angle

24. The angle formed by the congruent sides is called the vertex angle. The side opposite the vertex angle is called the base. base angle The two angles formed by the base and one of the congruent sides are called base angles.

25. The angle formed by the congruent sides is called the vertex angle. The side opposite the vertex angle is called the base. base angle The two angles formed by the base and one of the congruent sides are called base angles. leg

26. The angle formed by the congruent sides is called the vertex angle. The side opposite the vertex angle is called the base. base angle The two angles formed by the base and one of the congruent sides are called base angles. leg The congruent sides are called legs.

27. Classify each triangle by its angles and by its sides.

29. 120° 30°

30. Find the measures of XY and YZ of isosceles triangle XYZ if X is the vertex angle. Y X Z 102n + 2 2n - 2

31. Assignment: Pgs. 191-192 8-22 evens, 30-36 evens