Algebra 1: Unit 6 Lesson 8 - Percent Review

In this lesson, led by Kirk Weiler, the focus is on reviewing the concept of percentages, an essential foundation for understanding exponential functions that involve percentages. The lesson is structured around several key points and examples to help students grasp basic percent work and its applications in various contexts.

Fundamental Concept of Percent

• Percentages, a crucial concept extensively studied around seventh grade, compare two quantities in a proportional relationship as a ratio out of a hundred.
• Example provided: Converting a ratio to a percent (e.g., the ratio of left-handed students to all students in a class).

Problem Solving with Percents

Example Problems:

1. Calculating salary increases in dollars and as a percentage to understand increments in terms of money and relative growth.
2. Figuring out sales tax on a purchase (e.g., Gabe’s purchase of jeans) using the percent rate to calculate additional costs.
3. Predicting population decline of deer in a forest preserve by calculating the percentage decrease.

Methodology for Solving Percent Problems

• Emphasis on solving percent problems by converting percentages to decimals rather than relying on cross multiplication of proportions.
• Explanation on how to calculate percentages of a given quantity by multiplying the quantity by the decimal form of the percentage.

Key Takeaways:

• Understanding that a percentage is simply a fraction out of a hundred aids in simplifying calculations and practical applications.
• Mastering the conversion of percentages to decimals and vice versa is critical for efficiently solving a wide range of math problems.
• Real-world applications of percentages, such as calculating tips, sales tax, salary increases, and predicting population changes, demonstrate the importance of proficiency with percent calculations.

Kirk Weiler emphasizes the significance of feeling comfortable with basic percent work, given its extensive use in everyday life and in mathematical problems involving exponential functions.