1. ANGLES complete MJ p. 68 Number 1 and 2

2. Share your thoughts

3. You will learn to classify angles as acute, obtuse, right, or straight.

4. Here are some examples of angles.

5. We can identify an angle by using a point on each ray and the vertex. The angle below may be identified as angle ABC or as angle CBA; you may also see this written as ABC or as CBA. The vertex is always in the middle. vertex rays **We will Copy into your math notebooks at the end**

6. Angle Measurements We measure the size of an angle using degrees. Here are some examples of angles and their degree measurements.

7. Acute Angles An acute angle is an angle measuring between 0 and 90 degrees. **We will Copy into your math notebooks at the end**

8. Obtuse Angles An obtuse angle is an angle measuring between 90 and 180 degrees. **We will Copy into your math notebooks at the end**

9. Right Angles A right angle is an angle measuring 90 degrees. **We will Copy into your math notebooks at the end**

10. Straight Angle A straight angle is 180 degrees. **We will Copy into your math notebooks at the end**

11. Time to Review Be the first to raise your hand and correctly name what type of angle you see. The correct answer will be on the following slide!! Good luck!

13. Acute Angle

15. Obtuse Angle

17. Right Angle

19. Straight Angle

20. GREAT JOB!!

21. Measuring and Drawing Angles with a Protractor

22. Protractor Center Hole

23. Protractor Straight Edge

24. Protractor Curved Edge

25. 25 A 180 o Protractor

26. 18-Mar-1626 You need to be able to measure an angle to the nearest degree. To help you do this you should always: 1. Look directly down onto the cross point. 2. Always use the protractor in a horizontal manner as shown below.

27. Step 1: Place the center hole over the vertex of the angle

28. Step 2: Make sure you line up (make parallel) the straight edge with one side of the angle

29. Step 3: Find the point where the second side of the angle intersects with the curved edge

30. Step 4: Read the number on the protractor to find the measure of the angle Angle measures 50° MAKE SURE YOU READ THE RIGHT LINE….find where the zero is on the marked ray and then read the angle measurement….is your answer reasonable!?

31. 31 1 2 Measuring Angles with a 180 o Protractor 0 on the outside so use outside scale 0 on the inside so use inside scale 67 o 50 o Acute angles

32. 32 3 4 Measuring Angles with a 180 o Protractor 0 on the outside so use outside scale 0 on the inside so use inside scale 135 o 120 o Obtuse angles

33. What’s wrong with this picture? LINE IT WITH THE CENTER HOLE!!

34. Drawing Angles with a Protractor

35. Step 1: Draw a ray with the straight edge of the protractor

36. Step 2: Place the center hole over the starting point of the ray

37. Step 3: Place a dot at the angle measure required. For example…if you wanted to measure an acute angle of 60° you would place the dot here…

38. Step 4: Line up the straight edge over the starting point of the ray and the dot.

39. Step 5: Draw a ray connecting the two marks. The point at which they meet is called the vertex.

40. Half Circle Protractor

41. Let’s practice -Complete MJ p. 69 using your geometry template. -Get to know your protractor using SRB p. 163

42. Time to take notes ;)

43. vertex rays Vertex- the center of an angle where two or more rays meet. Rays- a line that has a starting point but no endpoint

44. An acute angle is an angle measuring between 0 and 90 degrees. An obtuse angle is an angle measuring between 90 and 180 degrees. A right angle is an angle measuring 90 degrees.

45. A straight angle is 180 degrees.