1. Parallel and Perpendicular Lines
Coordinate Algebra

2. Standard
G.GPE.5 Prove the slope criteria for parallel and perpendicular lines and use them to solve geometric problems (e.g., find the equation of a line parallel or perpendicular to a given line that passes through a given point).

3. Objectives
SWBAT determine if lines are parallel or perpendicular to eachother by looking at their slopes.
SWBAT find the equation of a line that is parallel or perpendicular to a given line passing through a given point.

4. Parallel Lines
Graphs: Lines never intersect and are in the same plane.
Equations: Same Slopes
Different y - intercepts

5. Writing Equations of Parallel Lines
Given equation should be solved for y ( y = mx + b).
Write down the slope of that line.
Substitute m and (x, y) in y = mx + b.
Solve for b.
Write the equation using m and b.

6. Perpendicular Lines Graphs: Lines intersect at 90° angle.
Equations: “Opposite” reciprocal Slopes
Different y - intercepts

7. Writing Equations of Perpendicular Lines
Given equation should be solved for y ( y = mx + b).
Write down the “opposite” reciprocal slope of that line.
Substitute slope and (x, y) in y = mx + b.
Solve for b.
Write the equation using m and b.