2. Geometry I Points, lines, segments, rays, and angles.

3. Points A point is an exact location, it can be so very tiny that it can’t be seen.A point is an exact location, it can be so very tiny that it can’t be seen. It can be located anywhere.It can be located anywhere. When we name a point, we use a capital letter.When we name a point, we use a capital letter. A A G G X T W

4. Line Segment A line segment is a line that begins at one point and ends at another. We name a line segment by naming the two points it connects and then placing a small line segment above the points’ names. We read it as segment RL, or segment LR. AB A B R U RU R L RL LR UR BA

5. Lines Lines go on and on in both directions.Lines go on and on in both directions. We name a line by writing the names of two points it crosses and placing a small line symbol above them.We name a line by writing the names of two points it crosses and placing a small line symbol above them. It is read line EM or line MEIt is read line EM or line ME E M EMME

6. Quick Review Line Segment…...Line Segment…... Read as segment RT or segment TRRead as segment RT or segment TR Line…...Line…... Read as line BY or lineYBRead as line BY or lineYB RT BY RT BY TR YB

7. Rays Rays begin at a certain point and then continue on and on. When we name a ray, we put it’s starting point first, then the name of the other point is crosses. We put a little ray sign above the name. ray RL.It is read ray RL. R L RL

8. Match the following... Match the shapes with their names.Match the shapes with their names. Read them.Read them. W D W D W D DW WD DW WD WD

9. Lines can be parallel - running alongside one another without ever touching.

10. Lines can be intersecting - crossing or meeting one another at some point. When lines intersect and make four square corners, they are perpendicular.

11. Angles Angles are formed when two lines intersect - meet or cross one another.Angles are formed when two lines intersect - meet or cross one another. The point where the sides of the angle meet is called the vertex.The point where the sides of the angle meet is called the vertex.

12. The Vertex The vertex is the point where the two sides of an angle meet one another.The vertex is the point where the two sides of an angle meet one another. The angle ‘s measurement is the measurement of the space between the sides of the angle.

13. Three Kinds of Angles You will be studying three kinds of angles.You will be studying three kinds of angles. They are named by their sizes.They are named by their sizes. It’s important to remember their names and sizes, it helps later when deciding what their measurement is on a half-circle protractor.It’s important to remember their names and sizes, it helps later when deciding what their measurement is on a half-circle protractor.

14. Right Angles Right angles are 90° - no more, no less. They form square corners, this helps to spot them.Right angles are 90° - no more, no less. They form square corners, this helps to spot them. 90°

15. Acute Angles ACUTE - is a small angle, less than 90°. Think of it as “a cute little guy”!ACUTE - is a small angle, less than 90°. Think of it as “a cute little guy”!

16. Obtuse Angles Obtuse angles are larger than 90° - think of them as “thick” or “fat” angles, another word for fat is obese - this might help you remember obtuse.Obtuse angles are larger than 90° - think of them as “thick” or “fat” angles, another word for fat is obese - this might help you remember obtuse.

17. Quick Review An ACUTE angle is less than 90°.An ACUTE angle is less than 90°. A RIGHT angle is exactly 90°. It forms a square corner.A RIGHT angle is exactly 90°. It forms a square corner. An OBTUSE angle is larger than 90°.An OBTUSE angle is larger than 90°.

18. Measuring Angles We measure angles with a protractor. There are two types - the half circle protractor...We measure angles with a protractor. There are two types - the half circle protractor...

19. Measuring Angles The circular protractor - it measures all the degrees in a full circle. There are 360° (degrees) in a full circle.

20. Using the Protractor To measure the degrees in an angle, we use the protractor.To measure the degrees in an angle, we use the protractor. We place the vertex of the angle in the place provided. We place the vertex of the angle in the place provided. We line up one side of the angle with the zero line and then read the measurement indicated by where the other side of the angle is located on the protractor. We line up one side of the angle with the zero line and then read the measurement indicated by where the other side of the angle is located on the protractor. Let’s see how that works…………….Let’s see how that works…………….

21. Put the vertex in the appropriate place Line up one side of the angle with the zero line of the protractor. Read the numbers where the other side of the angle points on the protractor.. 65° acute angle

22. Don’t get shook up if you put the angle to the left or right side of the protractor, just remember, ACUTE is less than 90°, RIGHT is exactly 90°, and OBTUSE is more than 90°. Read the numbers accordingly. 75° acute angle

23. Are you confused about which number to choose? Remember - ACUTE angles are LESS than 90°, so you pick the number that is less than the ninety. ACUTE angles are smaller than square corners. OBTUSE angles are LARGER than 90° so you pick the number that is more than ninety. OBTUSE angles are fatter or larger than square corners. OBTUSE angles are LARGER than 90° so you pick the number that is more than ninety. OBTUSE angles are fatter or larger than square corners. RIGHT angles are exactly 90°. RIGHT angles are exactly 90°. 106° obtuse angle

24. When using a circular protractor, line up one side of the angle with the zero line. Remember to put the vertex in the center. Read the numbers on the protractor that are indicated by the second side of the angle. Place the vertex in the center area which is marked. 60° acute

25. Review Name the following angles and tell if you would look for a number more or less than 90°.Name the following angles and tell if you would look for a number more or less than 90°. acute obtuse right obtuse acute less more less more

26. Read the Measurement 115° obtuse

27. Match the Terms Acute Angle Right Angle Obtuse Angle Angle that is exactly 90° Angle larger than 90° Angle less than 90°

28. ANY QUESTIONS? NOW is the time to ask questions or for a review.NOW is the time to ask questions or for a review.