1. SECTION 1.6 ANGLES AND THEIR MEASURE LEARNING TARGETS: 1. I will be able to measure and classify angles. 2. I will be able to understand and apply the Angle Addition Postulate. VOCBAULARY Angle, Sides, Vertex, Acute Angle, Right Angle, Obtuse Angle, Straight Angle

2. I NTRO TO A NGLES An angle consists of two rays that have the same endpoint. The rays are the sides of the angle. The endpoint is the vertex of the angle.

3. P ICTURE OF A NGLE

4. MEASURING ANGLES

6. EXAMPLE Name the three angles below. What is the vertex of all three angles?

7. EXAMPLE Name the angles in the figure. Measure each angle.

8. ACTIVITY 1.6 How do you classify angles based on their angle measure? Materials: 2 Pieces of Paper, Scissors, and Protractor Page 34

9. STEP 1: Cut a large corner off two pieces of paper. These are called RIGHT ANGLES.

10. S TEP 2: Cut each right angle into two smaller angles. Angles smaller than a right angle are called ACUTE ANGLES.

11. S TEP 3 Arrange three angles to form an angle larger than a right angle. Angles larger than a right angle are called OBTUSE ANGLES.

12. T HINK A BOUT I T … 1.Stack your angles on top of each other to compare their sizes. Arrange the angles from smallest to largest. 1.Choose two angles and place them next to each other to form a larger angle. Use a protractor to estimate the measure of the angle they form. What type of angle is it?

13. T HINK A BOUT I T … 3. Choose three angles and place them next to each other to form a larger angle. Use a protractor to estimate the measure of the angle they form. What type of angle is formed? 4. Arrange the four angles to form a straight angle, an angle with a measure of 180 degrees.

14. C LASSIFYING A NGLES Page 14 in Notes

15. EXAMPLE Classify each angle and justify your answer. m<G = 180° ___________________ m<H = 25° ____________________ m<J = 100° ___________________

16. C ONGRUENT A NGLES

17. CONGRUENT ANGLES NOTATION: How do you write that the angles below are congruent? NOTATION:

18. A NGLE A DDITION P OSTULATE

19. EXAMPLE ( I N T EXTBOOK )

20. EXAMPLE ( I N N OTES ) Angle Addition Postulate:

21. HOMEWORK Section 1.6 Assignment (PART 1) Page 38 #1-29 ALL Due Friday, 10/07