1. Warm Up Classify each angle as acute, obtuse, or right. 1. 2. 3. 3.
4. If the perimeter is 47, find x and the lengths of the three sides.

2. Objectives
Classify triangles by their angle measures and side lengths.
Use triangle classification to find angle measures and side lengths.

3. AB, BC, and AC are the sides of ABC.
A, B, C are the triangle's vertices.

4. Acute Triangle Three acute angles Triangle Classification
By Angle Measures
Acute Triangle
Three acute angles

5. Three congruent acute angles
Triangle Classification
By Angle Measures
Equiangular Triangle
Three congruent acute angles

6. Right Triangle One right angle Triangle Classification
By Angle Measures
Right Triangle
One right angle

7. Obtuse Triangle One obtuse angle Triangle Classification
By Angle Measures
Obtuse Triangle
One obtuse angle

8. Classify BDC by its angle measures.

9. Classify ABD by its angle measures.

10. Classify FHG by its angle measures.

11. Equilateral Triangle Three congruent sides Triangle Classification
By Side Lengths
Equilateral Triangle
Three congruent sides

12. At least two congruent sides
Triangle Classification
By Side Lengths
Isosceles Triangle
At least two congruent sides

13. Scalene Triangle No congruent sides Triangle Classification
By Side Lengths
Scalene Triangle
No congruent sides

14. Classify EHF by its side lengths.

15. Classify EHG by its side lengths.

16. Classify ACD by its side lengths.

17. Find the side lengths of JKL.

18. Find the side lengths of equilateral FGH

19. A steel mill produces roof supports by welding pieces of steel beams into equilateral triangles. Each side of the triangle is 18 feet long. How many triangles can be formed from 420 feet of steel beam?

20. 4. Find the side lengths of the triangle.
Lesson Quiz
Classify each triangle by its angles and sides.
MNQ
NQP
MNP
4. Find the side lengths of the triangle.

21. HomeWork pg219 4,6,10,14,16,18,30, 40,47,50,52,56