Find slope, equation, distance, midpoint & angle between two points
Slope = (y₂-y₁)/(x₂-x₁). It measures steepness between two points.
The line rises from left to right — as x increases, y increases.
The line falls from left to right — as x increases, y decreases.
A horizontal line where y₁=y₂. The line is flat.
A vertical line where x₁=x₂. Division by zero is undefined.
y = mx + b, where m is slope and b is the y-intercept.
Midpoint = ((x₁+x₂)/2, (y₁+y₂)/2), the point halfway between.
Distance = √((x₂-x₁)²+(y₂-y₁)²), the straight-line distance.