Final answer:
The primary concept emphasized in All Things Algebra's homework 4 under the 'Ratios, Proportions, and Percentages' unit is Unit Rates (option D) , which compare two measurements with one quantity being one, such as 55 miles per hour (55 miles/1 hour).
Step-by-step explanation:
In All Things Algebra's homework 4, part of the Ratios, Proportions, and Percentages unit, the primary concept emphasized is Unit Rates. A unit rate is defined as a comparison of two measurements where one of the quantities is one. For example, traveling at 55 miles per hour represents a unit rate, which is written as 55 miles/1 hour. This concept is central to understanding how different rates operate in various contexts, such as in scaling dimensions or comparing different quantities effectively.
Understanding how to work with and calculate unit rates is essential in real-world applications, such as determining the speed of a vehicle, the cost of goods per unit, or the scale on a map. Unit rates provide a standardized way to compare quantities, making them a vital concept within the broader topic of ratios and proportions.