Writing proportional equations

The  exercise appears under the 7th grade (U.S.) Math Mission. This exercise practices writing proportional equations and locating and understanding what makes them up.

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


 * 1) Write an equation for the proportion: This problem provides a situation or chart of information that represents a proportional relationship. The student is asked to write an equation to represent the relationship in the space.Wpe1.png
 * 2) Find the constant of proportionality: This problem provides a chart or other display of a proportional relationship. The student is asked to use the information to find the constant of proportionality.Wpe2.png

Strategies
Knowledge of direct variation, ratios, and proportions are encouraged to ensure success on this exercise.
 * 1) In a proportional relationship represented by $$y=kx$$, the constant of proportionality is the variable $$k$$.
 * 2) The equations that are created need not be simplified, so it can be more efficient to use whole numbers as opposed to fraction when writing an equation to represent a situation, such as $$ay=bx$$.

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.