1. 3 – 2 Ditto; HW Answers 8)x = 43 9)x = 90 10)x = 38 11)x = 100 12)x = 70 13) x = 48

2. Section 3 – 3 Parallel Lines & The Triangle Angle-Sum Theorem Objectives: To classify triangles and find the measures of their angles To use exterior angles of triangles

3. Triangle Angle-Sum Theorem: The sum of the measures of the angles of a triangle is 180.

4. Example 1 Applying the Triangle Angle-Sum Theorem A)Find m

5. B)Δ MNP is a right triangle. is a right angle and m is 58. Find m

6. Example 2 Using Algebra A)Find the values of x, y, and z.

7. B)Find the values of a, b, and c.

8. C)Find the values of x, y, and z.

9. Classifying Triangles By Angles

10. Classifying Triangles By Sides

11. Example 3 Classifying a Triangle A) Classify the triangle by its sides and its angles.

12. Draw and mark a triangle to fit each description. If no triangle can be drawn, write not possible. B)Acute Scalene C)Isosceles Right D)Obtuse Equiangular

13. Exterior Angle: An angle formed by a side and an extension of an adjacent side Remote Interior Angles: For each exterior angle, the two nonadjacent interior angles of the triangle

14. Triangle Exterior Angle Theorem: The measure of each exterior angle of a triangle equals the sum of the measures of its two remote interior angles.

15. Example 4 Using the Exterior Angle Theorem Find the measure of each missing angle.