Geometry Chapter 3.6 Parallel lines in the Coordinate Plane
I) Vocabulary:
A) Slope: (nonvertical line): Ratio of the vertical change (the rise, Δ y) to the horizontal change (the run, Δ x)
Formula: slope = m = (Δy/Δx) = (y2 - y1)÷ (x2 - x2)
II) Postulate:
A) In the coordinate plane, 2 nonvertical lines are parallel if and only if they have the same slope. Any two vertical or horizontal lines are parallel.
B) Equation of a line:
y = mx + b
where m is the slope of the line and b is the y-intersept (where it crosses the y-axis)
