Interpret and
Graph Proportional
Relationships
5-3
Does the relationship shown in the table represent a proportional
relationship? Explain how you know.
Does the relationship shown in the graph represent a proportional
relationship? Explain how you know.
Discrete Graph
●
only consists of certain distinct points – points that can be
counted or listed. (do NOT connect the dots).
Examples:
• The number of people in your class (no fractional parts of a person).
• The number of chocolates in a bag
• The number of questions on a math test (no incomplete questions).
• The number of strings on the guitar
NOTE:
Discrete data is counted. The description
of the task is usually preceded by the
words "number of...".
Continuous Graph
●
consists of all points within a given interval (including
up to infinity).
Examples:
• The height of a horse (could be any value within the range of horse heights).
• Time to complete a task (which could be measured to fractions of seconds).
• The outdoor temperature at noon (any value within possible
temperatures ranges.)
• The height of students in my classes throughout the day is a
continuous function (can have decimal answers).
• The speed of a car on Route 3 (assuming legal speed
limits).
NOTE:
Continuous data usually requires a
measuring device. (Ruler, stop watch,
thermometer, speedometer, etc.)
An airline is seating passengers on a plane at a constant rate.
The number of passengers seated is given in the table. Use
the information in the table to graph the number of passengers
seated over time.
1) Determine if the points should be connected with a line.
Because number of passengers seated is always a whole number, do not
draw a line to connect the points.
1) What does the point (15,12) describe?
The lunchroom is serving lunches at a constant rate. The
number of lunches served is given in the table. Use the
information in the table to graph the number of lunches served
over time.
1) What does the point (5,7) represent on the graph?
2) Did you represent the situation with a discrete graph or a continuous
graph? why?
Dina is reading pages of a book at a constant rate.
The table shows the time Dina takes to read certain numbers of
pages.
1)
2)
3)
4)
1
2
3
6
5
10
8
16
Graph the points in the table
What does the point (5,10) represent on the graph?
What is the unit rate per minute?
Did you represent the situation with a discrete graph or a continuous
graph? why?
5) How many pages can Dina read in 20 minutes?
An elevator is ascending at a constant rate. The height of the
elevator from the ground over time is given by y=4x ,
sdnoces ni dessap emit fo tnuoma eht stneserper x erehw
.teef ni rotavele eht fo thgieh eht stneserper y dna
1)Use the equation to complete the table.
2)Graph the height of the elevator in terms of the amount of time that has passed.
3)Look at the point on the graph at (1, 4). Describe what this point represents.