3.4 Small Group · Group 2
Second Challenge Form · Non-Routine Extension · Same Standard, New Problems
Graph Ratio Tables · Coordinate plane · Procedural Fluency · Real-World Applications
- You already can do this. So we go up a level, not up a number: find what is always true, show it a second way, and be ready to defend it with a reason instead of an answer.
- The recipe uses 2 ounces of sauce for every 1 sundae.
- I put sundaes on the x-axis and ounces of sauce on the y-axis.
- For 1 sundae I need 2 ounces, so I plot the ordered pair (1, 2): right 1, up 2.
- For 2 sundaes I need 4 ounces, so I plot (2, 4): right 2, up 4.
- When I connect (1, 2), (2, 4), (3, 6), they form a straight line through the origin (0, 0).
- A recipe uses 1 cup of sugar for every 3 cups of flour.
- For 1 cup of sugar, the ordered pair is (1, 3): right 1, up 3.
- For 2 cups of sugar, what is the pair? It is (2, 6): right 2, up 6.
- Now prove it: say why that move had to work at all — not just that it did.
- Sentence frame — convince a skeptic: "My method works because ___ . It would stop working if ___ ."
- Graph Ratio Tables (Representar tablas de razones en una gráfica) — Plot the paired values from a ratio table as ordered pairs.
- Coordinate plane (Plano cartesiano) — A grid with a line going across and a line going up to plot points.
- Ordered pair (Par ordenado) — Two numbers (x, y) that tell where a point is on a grid.
- Linear pattern (Patrón lineal) — Points that make a straight line on a grid.
- Proportional (Proporcional) — Two amounts that grow together at the same rate.
- Origin (Origen) — The point (0, 0) where the two grid lines cross.
- A common mistake in Graph Ratio Tables is writing the ordered pair in the wrong order — putting the second table value first instead of matching (x, y) to the table's column order. For example, if a recipe table shows 2 cups of sugar for every 4 cups of flour, a student might plot (4, 2) instead of (2, 4), landing the point in a completely different spot on the grid. Before you plot, check: which quantity goes on the x-axis, and does your ordered pair start with that number?
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1 MULTIPLE CHOICE
A ratio table shows (2, 6), (4, 12), and (6, 18). Which ordered pair comes next if the pattern continues?
- A(8, 24)
- B(7, 20)
- C(8, 22)
- D(10, 24)
✏️ Workspace & Solution Steps -
2 MULTIPLE CHOICE
When you graph equivalent ratios, the points will always form what shape?
- AA straight line through the origin
- BA curved line
- CA zigzag
- DA circle
✏️ Workspace & Solution Steps -
3 MULTIPLE CHOICE
Points from a ratio table are plotted at (1, 4), (2, 8), and (3, 12). What is the ratio of y to x for each point?
- A4:1
- B1:4
- C2:8
- D3:4
✏️ Workspace & Solution Steps -
4 MULTIPLE CHOICE
Two students graph ratio tables. Student A plots (1,2), (2,4), (3,6). Student B plots (1,3), (2,6), (3,9). Whose line is steeper?
- AStudent B
- BStudent A
- CSame steepness
- DCannot tell
✏️ Workspace & Solution Steps
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5 ERROR ANALYSIS
Fix our table's thinking
- 1The problem:Points from a ratio table are plotted at (1, 4), (2, 8), and (3, 12). What is the ratio of y to x for each point?
- 2A classmate at our table answered:1:4
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation -
6 ERROR ANALYSIS
On Level — Spot the Common Mistake
- 1Read the ratio:A recipe uses 4 cups of water for every 1 cup of rice (rule: y = 4x). A student is plotting points for the line.
- 2List the points:(1, 4), (2, 8), (3, 12)
- 3Add another point:The student also plots (4, 14) and says it belongs on the same line.
- 4Conclusion:All four points form a straight line.
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation
Writing Task: Justify why your mathematical solution is accurate and complete.