standard_description: Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in the coordinate plane; derive the equation y = mx for a line through the origin and the equation y = mx + b for a line intercepting the vertical axis at b.
problem_activity: Solve. Show or explain your work.
a.
$${{2\over3} \times {5\over6}}$$
b.
$${{4\over9} \times { 3\over 8}}$$


aligns: no