Edm 1 lines and angles
- 3. Line segments can be measured from beginning to end.ABWe mark a line segment with pointsThose points are labeled with lettersWe can name this line segment either:ABBA
- 4. Lines vs. Line SegmentsLines are different from line segments.We can see the beginning and ending of a line segment.Lines extend on foreverTo show the difference between a line and a line segment we use arrows instead of pointsABWe name a line by showing the arrows:AB
- 5. ABDCTwo line segments are shown hereABCD
- 6. When lines or line segments meet…ABDCThey intersect to form angles…
- 7. The point at the intersection is called the vertex.EADBWhen we name the angle, the vertex must be in the middleC
- 8. The point at the intersection is called the vertex.AEDEADBWhen we name the angle, the vertex must be in the middleorCDEAPoint E, the vertex, is alwaysin the middle
- 9. XNotice any angles?YACPBACXYZPQRJHIQZRBJIName these angles…H
- 10. ABDCWhen 2 line segments meet to form a 90° angle they called perpendicular line segments
- 11. A90°90°90°90°BDCPerpendicular lines intersect to form a 90° angle also referred to as a right angle.You can check if the angle right by holding up a piece of notebook paper.
- 12. PerpendicularA90°BDCWhere do we see right angles?
- 13. PerpendicularABDCWhere do we see right angles?
- 14. Let’s Look at the Strata Center again…Notice many perpendicular lines?Not quite 90°AASmaller than 90° again.BBDDCC
- 15. AABBDDCC
- 16. AABBDDCC
- 17. Acute Angle = Less than 90°AABBDDCCBoth of these angles are smaller than 90°Angles smaller than 90° are called acute
- 18. What about angles larger than 90°?
- 19. What about angles larger than 90°?Angles larger than 90° are called obtuseNotice all of the extra room?
- 20. If you extend these two lines segments will they ever touch?Right, if they did what might happen?
- 21. When two line segments on the same plane never touch they are calledParallelLots of parallel lines
- 22. Do these lines intersect?But, if you extend them outward, would they intersect?Are these lines parallel?No, but actually they are. It’s just the angle of the picture.
- 23. Examples of Parallel Lines