1. Parallel and Perpendicular Lines

2. Parallel Lines in Everyday Life

3. Parallel Lines
Parallel lines are two lines in the same plane with the same slope.
They never cross even if both lines were extended infinitely in both directions
Look back at our examples:
What would happen if the railroad tracks ever crossed?
What about if the yard lines on a football field weren’t the same distance apart at any point?
Why would the even bars in gymnastics need to be parallel?

4. Perpendicular Lines In Everyday Life

5. Perpendicular Lines
Perpendicular lines are two lines that intersect to form a right angle.
They only intersect at one point
Look back at our examples:
Why is plaid perpendicular?
Why are window panes perpendicular?
Why may an intersection need to be a 90 degree angle?

6. Skew Lines
Lines in the same plane that do not intersect and are not parallel.
Think of ideas in which you could find this to be possible.
What about if you were given a cube?

7. Skew Lines
Notice that the two green lines will never intersect yet they are not parallel

8. Parallel Planes
Lets consider the cube example again

9. Perpendicular Planes
Lets consider the cube example again

10. Perpendicular Planes
Consider if you had two pieces of paper and cut a slice in one. If they “intersected” their intersection would be a line.