1. Let's start by understanding the problem: you want to know why we use a particular formula and the logic behind it. 2. Formulas in math and science are concise ways to express relationships between quantities based on observed patterns or derived principles. 3. For example, consider the formula for the area of a rectangle: $$A = l \times w$$ where $l$ is length and $w$ is width. 4. This formula works because the area is the total number of unit squares that fit inside the rectangle, which is the product of its length and width. 5. The logic behind using formulas is to simplify complex problems into manageable calculations by capturing essential relationships. 6. When you understand the derivation or reasoning behind a formula, it becomes easier to apply it correctly and adapt it to new problems. 7. If you have a specific formula in mind, please share it, and I can explain the logic and derivation step-by-step.