1. 7-6 Triangles Course 2 Warm Up Warm Up Problem of the Day Problem of the Day Lesson Presentation Lesson Presentation

2. Warm Up 1.What is the name of a six-sided figure? 2. What is the definition of an acute angle? 3. The measure of one angle of two supplementary angles is 32°. What is the measure of the other angle? hexagon an angle that measures less than 90° 148° Course 2 7-6 Triangles

3. Problem of the Day Use 6 congruent line segments to form 4 equilateral triangles. (Hint:Use toothpicks or other objects to model the segments.) Place the segments so they form a pyramid. Course 2 7-6 Triangles

4. Learn to classify triangles by their side lengths and angle measures. Course 2 7-6 Triangles

5. Vocabulary scalene triangle isosceles triangle equilateral triangle acute triangle obtuse triangle right triangle Insert Lesson Title Here Course 2 7-6 Triangles

6. Course 2 7-6 Triangles One way to classify triangles is by the lengths of their sides. Triangles classified by sides A scalene triangle has no congruent sides.

7. Course 2 7-6 Triangles One way to classify triangles is by the lengths of their sides. Triangles classified by sides An isosceles triangle has at least 2 congruent sides

8. Course 2 7-6 Triangles One way to classify triangles is by the lengths of their sides. Triangles classified by sides In an equilateral triangle, all of the sides are congruent.

9. Course 2 7-6 Triangles One way to classify triangles is by the lengths of their sides. Another way is by the measures of their angles. Triangles classified by angles In an acute triangle, all of the angles are acute.

10. Course 2 7-6 Triangles One way to classify triangles is by the lengths of their sides. Another way is by the measures of their angles. Triangles classified by angles An obtuse trianglehas one obtuse angle.

11. Course 2 7-6 Triangles One way to classify triangles is by the lengths of their sides. Another way is by the measures of their angles. Triangles classified by angles A right triangle has one right angle.

12. Course 2 7-6 Triangles When classifying a triangle according to its sides and angles, use the word that describes the sides first, and use the word that describes its angles second. Writing Math

13. Classify each triangle according to its sides and angles. Additional Example 1A & 1B: Classifying Triangles Course 2 7-6 Triangles A. Two congruent sides acuteThree acute angles This is an isosceles acute triangle. 5 ft 9 ft B. No congruent sides rightOne right angle This is a scalene right triangle. 24 m 25 m 7 m isosceles scalene

14. Classify each triangle according to its sides and angles. Additional Example 1C & 1D: Classifying Triangles Course 2 7-6 Triangles C. No congruent sides acuteThree acute angles This is a scalene acute triangle. D.Three congruent sides acuteThree acute angles This is an equilateral acute triangle. scalene equilateral

15. Try This: Example 1A & 1B Insert Lesson Title Here Course 2 7-6 Triangles Classify each triangle according to its sides and angles. A. Two congruent sides obtuseOne obtuse angle This is an isosceles obtuse triangle. B. Two congruent sides rightOne right angle This is an isosceles right triangle. 5 ft 3 ft isosceles

16. Try This: Example 1C & 1D Insert Lesson Title Here Course 2 7-6 Triangles Classify each triangle according to its sides and angles. C. No congruent sides obtuse One angle exceeding 90° This is a scalene obtuse triangle. D.No congruent sides obtuseOne angle exceeding 90° This is a scalene obtuse triangle. scalene

17. Identify the different types of triangles in the figure, and determine how many of each there are. Additional Example 2: Identifying Triangles Course 2 7-6 Triangles TypeHow manyName Scalene 2 ABD,BCD Isosceles Right Obtuse Acute ACE, ABC ABD,BCD ACE ABC 2 2 1 1

18. Try This: Example 2 Insert Lesson Title Here Course 2 7-6 Triangles A B C D E F G H I J Identify the different types of triangles in the figure, and determine how many of each there are. Isosceles Obtuse Acute 5 2 4 NameHow manyType DJA,JDG HJI,BCD DFE DJA,ADG JDG,JHI, BCD,DEF

19. Lesson Quiz Classify each triangle according to its side or angle measures. 1. 7ft, 8ft, 12ft 2. 45°, 90°, 45° 3. 12, 9, 12 4. 120°, 20°, 40° 5. Identify the different types of triangles in the figure and determine how many of each there are. right scalene Insert Lesson Title Here isosceles obtuse Course 2 7-6 Triangles 1 isosceles acute triangle, 1 equilateral triangle, 1 scalene right triangle