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: Task
Plot the points (5,3), (-1,1), and (2,-3) in the coordinate plane and find the lengths of the three segments connecting the points.
Find the distance between (5,9) and (-4,2) without plotting the points.
If $(u,v)$ and $(s,t)$ are two distinct points in the plane, what is the distance between them? Explain how you know.
Does your answer to (c) agree with your calculations in parts (a) and (b)? Explain.


aligns: no