Mathematics Grade 7 15 min

Solve the proportion

Solve the proportion

Tutorial Preview

1

Introduction & Learning Objectives

Learning Objectives Identify and write proportions involving decimal values. Apply the Cross-Multiplication Property to set up equations from proportions. Solve one-step linear equations containing decimal coefficients or constants. Accurately perform multiplication and division operations with decimals to find unknown values in proportions. Verify the solution to a proportion by substituting the found value back into the original equation. Solve real-world problems by setting up and solving proportions that include decimals. Ever wondered how chefs adjust recipes for more or fewer people, or how maps shrink the real world? 🗺️ It's all about keeping things in proportion! In this lesson, you'll learn how to solve equations called proportions, especially when they i...
2

Key Concepts & Vocabulary

TermDefinitionExample RatioA comparison of two quantities by division.If a recipe uses 0.5 cups of sugar for 1 cup of flour, the ratio of sugar to flour is 0.5:1 or $\frac{0.5}{1}$. ProportionAn equation that states two ratios are equal.$\frac{0.5}{1} = \frac{x}{2}$ is a proportion. Terms of a ProportionThe four numbers or expressions that make up a proportion.In $\frac{a}{b} = \frac{c}{d}$, the terms are $a, b, c, d$. ExtremesThe first and last terms of a proportion (the outer terms).In $\frac{a}{b} = \frac{c}{d}$, $a$ and $d$ are the extremes. MeansThe middle terms of a proportion (the inner terms).In $\frac{a}{b} = \frac{c}{d}$, $b$ and $c$ are the means. Cross ProductsThe product of the means and the product of the extremes. In a true proportion, these products are equal.For $\frac{a}...
3

Core Formulas

Definition of a Proportion $\frac{a}{b} = \frac{c}{d}$ A proportion is an equation stating that two ratios are equivalent. Here, $a, b, c, d$ are numbers, and $b \neq 0, d \neq 0$. Cross-Multiplication Property If $\frac{a}{b} = \frac{c}{d}$, then $ad = bc$. In any true proportion, the product of the extremes ($a \cdot d$) is equal to the product of the means ($b \cdot c$). This property is fundamental for solving for an unknown variable. Solving for an Unknown in a Proportion If $N \cdot x = M$, then $x = \frac{M}{N}$. After applying cross-multiplication, you will often have a linear equation where a number is multiplied by the variable. To find the variable, divide both sides of the equation by the number multiplying the variable.

5 more steps in this tutorial

Sign up free to access the complete tutorial with worked examples and practice.

Sign Up Free to Continue

Sample Practice Questions

Challenging
First, solve for 'a' in the proportion $\frac{a}{1.5} = \frac{2.4}{3}$. Then, use that value of 'a' to find 'b' in the proportion $\frac{a}{b} = \frac{0.4}{5.5}$. What is the value of 'b'?
A.1.2
B.13.75
C.16.5
D.0.08
Challenging
Given the proportion $\frac{x}{2.5} = \frac{y}{1.5}$, which equation correctly expresses x in terms of y?
A.$x = \frac{5}{3}y$
B.$x = 0.6y$
C.$x = y + 1.0$
D.$x = 3.75y$
Challenging
A machine fills 6 bottles in 7.5 seconds. At this constant rate, how many *minutes* will it take to fill 240 bottles?
A.300 minutes
B.1.25 minutes
C.1800 minutes
D.5 minutes

Want to practice and check your answers?

Sign up to access all questions with instant feedback, explanations, and progress tracking.

Start Practicing Free

More from Operations with decimals

Ready to find your learning gaps?

Take a free diagnostic test and get a personalized learning plan in minutes.