ACT prep: Best formulas to remember?

Hey everyone! I'm prepping for the ACT, and I'm wondering if any of you have suggestions on key formulas I should definitely memorize before the test? Any tips would be greatly appreciated!

Hello! Here's a list of some key formulas and concepts you should definitely memorize for the ACT math section:

1. Distance-Rate-Time: Distance = Rate × Time

2. Slope: m = (y2 - y1) / (x2 - x1)

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

4. Area of a Triangle: A = (1/2)bh, where b is the base and h is the height

5. Quadratic Formula: x = (-b ± √(b^2 - 4ac)) / (2a) for ax^2 + bx + c = 0

6. Pythagorean Theorem: a^2 + b^2 = c^2, applicable for right triangles

7. SOHCAHTOA (trigonometry): Sin θ = Opposite / Hypotenuse, Cos θ = Adjacent / Hypotenuse, Tan θ = Opposite / Adjacent

8. Special right triangles: 45-45-90 triangle ratios (1:1:√2) and 30-60-90 triangle ratios (1:√3:2)

9. Circles: Circumference = 2πr, Area = πr^2

10. Arc length in a circle: (θ/360) × 2πr, where θ is the central angle in degrees and r is the radius

11. Volume of geometric solids: Rectangle Prism (lwh), Cylinder (πr^2h), Sphere (4/3πr^3), and Cone (1/3πr^2h)

12. Average: Average = (Sum of terms) / (Number of terms)

13. Probability: P(event) = (Number of ways an event occurs) / (Total number of possible outcomes)

14. Factors of a number: Numbers that can evenly divide and give you a whole number quotient

15. Percent change: (New Value - Old Value) / Old Value × 100%

Make sure to practice problems using these formulas and concepts, so you can quickly identify when to use them during the test. Good luck with your ACT prep!