Proportions are also a valuable tool in business. If the time it takes to do a task is directly related to the cost the business has to charge for that task, any task can be evaluated for the cost. Set up a proportion and solve it to demonstrate this type of business application. (An example might be 5 hours / $20 = 10 hours / x). Remember that setting the cross products (multiplications) equal, and then solving for x is the way to solve a proportion.
Equations are used to demonstrate many different things. In the equation C = 0.17x, C stands for cost and x stands for the number of kilowatt hours of electricity a business might use in a month. Determine the cost of electricity for 1,000, 1,500, and 3,000 kilowatt hours of usage. Also, show how C / .17 = x is can be used to determine how many kilowatt hours have been used if you know cost and rate per kilowatt hour ($0.17). Find an electric bill for your home or apartment and determine the cost per kilowatt hour, or research your power provider for this information. Share your findings with the class.