Interpreting graphs of proportional relationships

The  exercise appears under the 7th grade (U.S.) Math Mission. This exercise explores the graphical representation of proportional relationships and asks questions about the graph.

Types of Problems
There are two types of problems in this exercise:


 * 1) Determine which of the statements are true: This problem provides a graph of a proportional relationship and two possible statements that could be read from the graph. The student is asked to determine which, if either, of the statements are true.Igopr1.png
 * 2) Use the graph to answer the question: This problem provides the graph of a proportional relationship and asks a question based upon it. The student is expected to find the correct answer to the question being asked.Igopr2.png

Strategies
Knowledge of direct variation, ratios, proportions and graphing linear equations are encouraged to ensure success on this exercise.
 * 1) A direct variation, or proportional relationship, can be represented by $$y=kx$$.
 * 2) The constant of proportionality, or k from the above equation, is the slope of the line.
 * 3) The question asked is often about a rate or a value for a certain about.
 * 4) The labeling of the axes can be used to assist when trying to determine if a statement is true or not.

Real-life Applications

 * 1) Several problems on this exercise are real-life applications.
 * 2) Rates provide a real-life application of proportional relationships and are used in chemistry and physics.