Top 15 SAT Math Formulas to Memorize (Not on Reference Sheet)
Must-know formulas not provided on the exam reference sheet.
The top formulas NOT provided on the SAT reference sheet that you must memorize are: 1. Vertex of a Parabola: x = -b/(2a). 2. Discriminant: b² - 4ac. 3. Circle Equation: (x-h)² + (y-k)² = r². 4. Slope: m = (y₂-y₁)/(x₂-x₁). 5. Quadratic Formula: x = (-b ± √(b²-4ac))/(2a). 6. Percent Change: |New - Old|/Old × 100.
While the SAT provides geometry formulas (area, volume, Pythagorean theorem), all algebra, quadratic, exponential, and coordinate formulas must be memorized.
Step-by-Step Breakdown & Rules
1. Vertex x-coordinate of Parabola
x = -b / (2a)
2. Vertex Form of Parabola
y = a(x - h)² + k (Vertex is at (h, k))
3. The Discriminant
D = b² - 4ac (D > 0: 2 real roots, D = 0: 1 real root, D < 0: no real roots)
4. Circle Equation in xy-plane
(x - h)² + (y - k)² = r² (Center (h, k), Radius r)
5. Slope-Intercept Form
y = mx + b (Slope m, y-intercept b)
6. Slope Formula
m = (y₂ - y₁) / (x₂ - x₁)
7. Exponential Growth & Decay
y = a(1 ± r)^t or y = a · b^t
8. Percent Change Formula
Percent Change = |New Value - Old Value| / (Old Value) × 100%
9. Sum and Product of Roots (Vieta's)
Sum of roots = -b/a, Product of roots = c/a
10. Distance Formula
d = √[(x₂ - x₁)² + (y₂ - y₁)²]
11. Midpoint Formula
M = ((x₁ + x₂)/2, (y₁ + y₂)/2)
12. Trigonometric Complementary Identity
sin(x°) = cos(90° - x°)
13. Arc Length & Sector Area in Radians
Arc Length s = rθ, Sector Area A = 1/2 · r²θ
14. Difference of Squares
a² - b² = (a - b)(a + b)
15. Quadratic Formula
x = [-b ± √(b² - 4ac)] / (2a)
Key Takeaways & Pro Tips
Frequently asked questions
What formulas are on the SAT Reference Sheet?
The Reference Sheet includes area of circle, rectangle, triangle, circumference, volume of rectangular prism, cylinder, sphere, cone, pyramid, special right triangles (30-60-90, 45-45-90), and Pythagorean theorem.
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