Identifying proportional relationships

The topic  appears under the 7th Grade Math Mission. This exercise introduces has several problems that attempt to help the user better understand direct variation.

Types of Problems
There are three types of problem in this exercise:


 * 1) Determine if the relationship is proportional: This problem provides a given graph, chart or word problem and asks the student to determine whether they relationship is proportional or not. The answer is given in a multiple choice format.Aaipr1.png
 * 2) Fill in missing information and determine if the relationship is proportional: This problem provides information and a partially filled in chart, or T-table. The student is asked to complete the missing information and determine if the relationship is proportional.Aaipr2.png
 * 3) Create graph and determine if the relationship is proportional: This problem has a grid on which the student is asked to create a graph representing some information. In addition, the student is asked to determine if the given relationship is proportional or not.Aaipr3.png

Strategies
This concept is almost identical to direct variation, so knowledge of direct variation will assist with doing these problems correctly.
 * 1) It is said that y varies directly with x if y=kx, or equivalently if y/x=k for a constant k.
 * 2) A proportional relationship must go through the origin so determining if a relationship is proportional can be done very quickly with a graph.
 * 3) To increase speed, find the ratio of output to input in two cases. In a proportional relationship these will be identical.