Proportional Reasoning Section 2.3. Objectives:  To solve problems using proportional reasoning.  Use more than one method to solve proportional reasoning.

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Presentation transcript:

Proportional Reasoning Section 2.3

Objectives:  To solve problems using proportional reasoning.  Use more than one method to solve proportional reasoning problems.

What Is A Proportion?  Proportions are two ratios set equal to each other  Example:

How Do You Know If A Proportion Is True?  The cross-products of the ratios must be equal. Ex. Cross-Product… 4 x 10 = 40 and 5 x 8 = 40 It is a proportion!

Proportions & Variables  Proportions may contain a variable.  Example:

Solving Proportions That Contain Variables  To solve for the variable you… CROSS MULTIPLY Step 1 Step 2 Step 3 Step 4 Step 5

Your Turn… Solve the following proportion:

Word Problems Using Proportions There is a ratio of 8 boys to 12 girls in a classroom. How many girls would there be if there were 12 boys in the classroom?

Homework 2.3 Proportions Worksheet