🔑 Key Concepts
- A proportion shows that two ratios are equivalent.
- Ratio word problems often describe a relationship between two quantities.
- When one quantity is multiplied by a scale factor, the related quantity must be multiplied by the same scale factor.
- Tables help organize the two quantities and keep the ratio order clear.
- Always match the correct labels, such as orange juice with orange juice and fruit punch with fruit punch.
✏️ Worked Examples
🧠 Math Vocabulary
- Ratio: a comparison of two quantities.
- Proportion: an equation showing that two ratios are equal.
- Equivalent ratios: ratios that describe the same relationship.
- Scale factor: the number used to multiply both quantities in a ratio.
- Ratio table: a table used to organize pairs of equivalent ratios.
💡 Main Idea
Many ratio word problems can be solved by finding the scale factor between two matching quantities. Once you know how one quantity changes, multiply the other quantity by the same factor to keep the ratios equivalent.
📚 What You Should Already Know
Students should know how to multiply whole numbers, identify the two quantities in a word problem, organize information in a table, and recognize equivalent ratios.
🚀 What Comes Next
After using scale factors to solve proportion problems, students can move toward unit rates, double number lines, percent problems, and proportional relationships on graphs and tables.
🧩 Embed This Video in Your LMS
Teachers can embed this YouTube video directly into Canvas, Google Classroom, Schoology, or another learning platform. Click below to show the embed code.