Use similar triangles to explain why the slope, ๐, is the same between any two distinct points on a non-vertical line in the coordinate plane; know the equation ๐ฆ = ๐๐ฅ for a line through the origin and the equation ๐ฆ = ๐๐ฅ + ๐ for a line intercepting the vertical axis at ๐.

Expressions and Equations

- Understand the connections between proportional relationships, lines and linear equations.