1. Notes 4.1– USING GRAPHS TO RELATE TWO QUANTITIES

2. Graphs can be used to show the CHANGING relationships between quantities.  
Key Phrase
Graph Meaning
Sketch of Graph
Line or curve that goes up from left to right
Line or curve that goes down from left to right
Horizontal line
Vertical Line y x
INCREASE, RISE, FAST
DECREASE, FALL, SLOW y x
CONSTANT, UNCHANGING y x
IMMEDIATE FALL, RISE y x

3. The variables are TIME in days, and GAS in gallons
Analyzing a Graph: The graph below shows the amount of gasoline in Jamie’s tank after she fills up her car. What are the variables? Describe how they are related at various points on the graph. 1 2 3 4 5 6 7
Gas (Gallons)
Time (days)
The variables are TIME in days, and GAS in gallons
Break the graph into sections!

4. 1.) Jamie does not drive the car for 5 days
Gas (Gallons)
Time (days) 1 2 3 4 5 6 7
1.) Jamie does not drive the car for 5 days
2.) Jamie drives the car and uses gas for 2 days.
3.) Jamie does not drive the car for 3 days
4.) Jamie drives the car and uses gas for 2 days.
5.) Jamie fills the tank with gas on the 12th day.
6.) Jamie drives the car and uses gas for 4 days.
7.) Jamie does not drive the car for 3 days

5. Matching a Graph and a Table: Match the graphs to the tables:
1.) ) )
A.) B.) C.)

6. You can use graphs to represent visually the relationship between
two variable quantities as they CHANGE.
Sketch a graph to represent the situation. Label each section.
1) You buy two shirts. The third one is free.
COST ($)
SHIRTS

7. BODY TEMP(Degrees) TIME (Min)
2) You warm up for gym class, play basketball, and then cool down.
BODY TEMP(Degrees)
TIME (Min)

8. HOMEWORK: 4.1 Practice WS