Ratios and Proportions: Proportions in Problem Solving

Objectives:

• The students will learn how to identify the quantities in a word problem that are being compared.

• The students will learn how to express those comparisons as ratios and proportions.

• The students will learn how to write the proportion using a variable as the unknown.

• The students will practice solving those proportions.

Suggested Grades:

Sixth Grade - Seventh Grade - Eighth Grade - Ninth Grade - including special education students

Lesson Procedure:

Print the classroom lesson plan and worksheet questions (see below).

Lesson Excerpt:

- "Today we are going to continue our work with ratios and proportions, but this time we are going to be using proportions in problem solving. Whenever we are comparing things in a problem, it makes sense to use a proportion to figure out any unknowns. Let's look at an example."
- On Board: The Smith family drinks 3 gallons of milk over a two-week period. At this rate, how many gallons of milk will they drink in 6 weeks?
- "Let me use this example to show you how to use a proportion to solve a problem. The first thing that we need to do when working on a word problem like this, is to set up the ratios. To do that, we need to ask the question "What is being compared?"

Continued...