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What are some crucial math formulas I should definitely know before taking the SAT? Can anyone recommend a comprehensive list or resource?

There are several key formulas and concepts you should be familiar with before taking the SAT mathematics section. Here's a list of some of the most important ones:

1. Linear equations: y = mx + b, where m is the slope and b is the y-intercept.

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

3. Quadratic formula: x = (-b ± √(b² - 4ac)) / (2a), where ax² + bx + c = 0.

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

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

6. Perimeter and area of rectangles: P = 2(l+w), A = lw

7. Circumference and area of circles: C = 2πr or πd, A = πr²

8. Triangle area: A = (1/2)bh

9. Pythagorean theorem: a² + b² = c² (for right triangles)

10. Special right triangles: 45-45-90: x : x : x√2, and 30-60-90: x : x√3 : 2x

11. Trigonometric ratios (for right triangles): sine (sin), cosine (cos), and tangent (tan)

12. Probability: P(event) = (number of successful outcomes) / (number of total outcomes)

13. Fractions, decimals, and percents conversions

14. Average: (sum of terms) / (number of terms)

15. Systems of equations: solving for variables using substitution or elimination.

While this list should provide a solid foundation, it is by no means exhaustive. For a more comprehensive list of SAT math formulas, I recommend visiting the College Board's website or checking out ºÚÁϲ»´òìÈ’s free SAT Guide. These resources are specifically tailored to the SAT and should give you the necessary tools to properly prepare. Additionally, practice tests will help you become familiar with how these formulas are used in context. Good luck!