Lesson 4: Determine Equivalent Ratios Using Graphs6.AT.3a

I can…

I can graph the values from a ratio table as points on the coordinate plane.

Key words

• Graph Ratio Tables — Plot the paired values from a ratio table as ordered pairs.
• Coordinate plane — A grid with a line going across and a line going up to plot points.
• Ordered pair — Two numbers (x, y) that tell where a point is on a grid.
• Linear pattern — Points that make a straight line on a grid.
• Proportional — Two amounts that grow together at the same rate.
• Origin — The point (0, 0) where the two grid lines cross.
• Ratio table — A table of equal ratios that shows a pattern.
• Unit rate point — The point (1, r) on a graph, where r is the amount for one.
• Interpret — Say in words what a point on a graph means.
• Coordinates — The x-value and y-value that locate a point.

Steps

1. The recipe uses 2 ounces of sauce for every 1 sundae.
2. I put sundaes on the x-axis and ounces of sauce on the y-axis.
3. For 1 sundae I need 2 ounces, so I plot the ordered pair (1, 2): right 1, up 2.
4. For 2 sundaes I need 4 ounces, so I plot (2, 4): right 2, up 4.
5. When I connect (1, 2), (2, 4), (3, 6), they form a straight line through the origin (0, 0).

Try it

A table compares the number of tricycles to the number of wheels: (1, 3), (2, 6), (3, 9). Which point would also be on the straight line through these points?

Check your answer

(5, 15)

The ratio is 1:3, so 5 tricycles have 5 × 3 = 15 wheels. The point (5, 15) continues the pattern.

Sentence starter

I know ___ because ___.

Goal: I can explain my graph using the words coordinate plane, ordered pair, origin, and proportional.