Learn how to apply proportions to solve real-world problems in this comprehensive prealgebra lecture. Explore various practical examples, including tire calculations, gallon measurements, gas consumption, defective product analysis, and profit calculations. Gain insights into setting up proportions, solving equations, and using calculators effectively. Understand the relationship between profit and cost, and learn how to determine actual profit. This in-depth tutorial provides a solid foundation for applying mathematical concepts to everyday situations, enhancing problem-solving skills in the process.