Proportions

Skill MaintenancePage 61

Commutative Property

• Addition 3 + 4 = 4 + 3 5 + 17 + 43 = 17 + 43 + 5

• Multiplication 3 * 4 = 4 * 3 2 * 7 * 8 = 8 * 2 * 7

Substitution

• Important concept when working with variables

• Substitution: Replace a variable with a number value

Ratios

• Ratio: Compares two numbers– Represent a part-to-whole relationship– Represent a part-to-part relationship

• Fraction is a special type of ratio (part-to-whole)

Variables in Formulas

• One of the most powerful uses of variables in formulas.

• We use substitution to replace the values we know.

• Variables and formulas help solve problems in geometry.

Proportions

• Proportion: Two ratios that are equal• Work for multiplication type ratios

Apply SkillsPage 62

Word Problems with Proportions

Word Problems with Proportions

Read the problem

What is the problem asking?

What do we Know?

Problem Solving ActivityPage 63

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