Objective: To represent mathematical relationships using graphs

Section 4-1 Using Graphs to

Relate Two Quantities

*Warm up: • Think about a real world example

where something is dependent on time?

• Can you think of another real world example of two things being dependent of each other (w/o using time)

a) The graph shows the volume of air in a balloon as you blow it up, until it pops.

• What are the variables?

• Describe how the variables are related at various points on the graph.

Problem #1: Analyzing a Graph

• What are the variables in the graph?

• Describe how the variables are related at various points on the graph.

Problem #1: Analyzing a Graphb) The graph shows the length of a board as time increases.

• What are the variables in the graph?

• Describe how the variables are related at various points on the graph.

Problem #1 Got It?The graph shows the cost of a cell phone as the number of minutes of calls increases.

a) A band allowed fans to download its new video from its Web site. The table shows the total number of downloads after 1, 2, 3, and 4 days. Which graph could represent the data shown in in the table?

Problem #2: Matching a Table & a Graph

b) The table shows the amount of sunscreen left in a can based on the number of times the sunscreen has been used. Which graph could represent the data shown in the table?

Problem #2: Matching a Table & a Graph

Problem #2 Got It?The table shows the total number of customers at a car wash after 1, 2, 3, and 4 days of its grand opening. Which graph could represent the data shown in the table?

a) A model rocket rises quickly and then slows to as stop as its fuel burns out. It begins to fall quickly until the parachute opens, after which it falls slowly back to Earth. What sketch of a graph could represent the height of the rocket during its flight? Label each section.

Problem #3: Sketching a Graph

b) Suppose you start to swing yourself on a playground swing. You move back and forth and swing higher in the air. Then you slowly swing to a stop. What sketch of a graph could represent how your height from the ground might change over time? Label each section.

Problem #3: Sketching a Graph

If you jumped from the swing instead of slowly swinging to a stop, how would the graph be different?

Problem #3 Got It?When Matt jogs on the treadmill, he gradually increases his speed until he reaches a certain level. Then he jogs at this level for several minutes. Then he slows to a stop and stretches. After this he increases to a speed that is slightly higher than before and jogs at this speed for a short while before slowing to a stop again. What is a possible sketch of a graph that shows Matt’s jogging speed during his workout? Label each section.

*HomeworkTextbook Page 237 – 238; #1 – 13 All