Summary: Perpendicular and Parallel Lines

Perpendicular and Parallel Line                          October 13, 2011

OBJECTIVE: SWBAT DESCRIBE THE SIMILARITIES OF ┴ (PERPENDICULAR LINES) AND ║ (PARALLEL LINES)

Today in class we learned about perpendicular and parallel lines. This was actually kind of easy. All you have to know for parallel lines is that lines are parallel if they have the same slope. For perpendicular lines, if they have the same y-intercept they will eventually intersect. Also, for perpendicular lines, you use multiplicative inverse for the slope. For example, 1/2, the inverse is -2/1 because you want the opposite of ½ so it has to be negative. Some examples are shown below.

EXAMPLES:

Parallel Lines-

~Remember to make lines parallel, they have to have the same slope~

y=2/3x+4

y=2/3x+6

*To make this parallel with the equation above, change the y intercept*

Perpendicular Lines-

~Remember to make lines perpendicular, you have to use multiplicative inverse~

y=3x+2

y=-1/3x+2

*If they have the same y-intercept, they will eventually intersect*