1. Geometry 3.4 Big Idea: Find the Slope of a Line. Determine if lines are parallel or perpendicular.

2. Reminders: Slope = steepness of a line

3. Positive Slopes : rise to right Negative Slopes : fall to right

4. Zero Slopes : horizontal lines Z Undefined Slopes : vertical lines(No slope) N

5. The greater the absolute value of the slope, the steeper the line.

6. Find the slope of a line that passes through(-1, 3) and (3, 2). Find the slope of a line that passes through (-1, 1) and (2, 0). Which line is steeper?

7. Postulate 17: Slopes of Parallel Lines In a coordinate plane, two nonvertical lines are ║ if and only if they have the same slope. (Any 2 vertical lines are parallel.)

8. Postulate 18: Slopes of Perpendicular Lines In a coordinate plane, two nonvertical lines are ┴ if and only if the product of their slopes is -1. (All horizontal lines are ┴ to all vertical lines.)

9. Find the slope of the line that passes through (- 1, 3) and (4, 1). Find the slope of the line that passes through (- 2, -1) and (3, -3). Are these lines parallel or perpendicular?

10. Find the slope of the line that passes through (2, 5) and (5, 3). Find the slope of the line that passes through (3, 0) and (7, 6). Are these lines parallel or perpendicular?

11. Graph Graph the line through the given point with the given slope.

12. Graph Graph the line through the given point with the given slope.