Must-know math formulas for the ACT?

Hello all, I'm in the process of preparing for the ACT, and I was wondering if there's a list of must-know math formulas that I should memorize? I want to make sure I'm covering all my bases. Thanks in advance!

Hello! I'm glad you're working on preparing for the ACT Math section. While the test usually provides some formulas, it's still beneficial to familiarize yourself with the essential ones to save time during the test. Here's a list of must-know math formulas to help you out:

1. Area of a rectangle: A = length × width

2. Area of a triangle: A = (base × height) / 2

3. Area of a parallelogram: A = base × height

4. Area of a circle: A = π × (radius²)

5. Circumference of a circle: C = 2 × π × radius

6. Pythagorean Theorem: a² + b² = c² (For right triangles, where a and b are the legs, and c is the hypotenuse)

7. Slope of a line: m = (y2 - y1) / (x2 - x1)

8. Slope-Intercept form of a line: y = mx + b (where m is the slope, and b is the y-intercept)

9. Distance formula: d = √[(x2 - x1)² + (y2 - y1)²]

10. Midpoint formula: M = ((x1 + x2)/2 , (y1 + y2)/2)

11. Quadratic formula: x = [-b ± √(b² - 4ac)] / 2a

12. Number of distinct permutations: (n!)/(n1! × n2! ×...× nk!) (where n is the total number of items, and n1, n2,..., nk are the individual types of items)

13. Probability of an event: P(Event) = (Number of successful outcomes) / (Total possible outcomes)

14. Average (Mean): Sum of numbers ÷ Total number of numbers

15. Percentage change: ([New value - Old value] ÷ Old value) × 100%

Remember, you don't want to just memorize these formulas, but also understand how they apply to various problem types and practice solving problems using them. Good luck with your ACT preparation!