Grade 7 · Unit 1 · Lesson 4 · part 2 of 7
Plot the lemonade
In Lesson 2 you tested the lemonade table by dividing.
Plot the lemonade
In Lesson 2 you tested the lemonade table by dividing. Now test it with a picture. Plot each row as a point: cups across, cost up. Click the crossing for each point, check them, then press Draw the line.
The points line up in a straight line, and that line goes right through the origin, the point (0, 0), where both amounts are zero. Zero cups, zero dollars. That is the graph test.
The graph test A proportional relationship is a straight line through the origin. Both things have to be true: straight, and through (0, 0).
A proportional relationship always multiplies by the same number, the unit rate.